Do I Lose Historical Sales Data When I Switch Inventory Software?

You do not have to start your garage’s history from zero when you change software. But keeping the old records and seeing them inside the new system are separate jobs. Neither should be left until after you cancel the old contract.

For a small workshop, the worry is practical. A customer rings about work done last winter. You need the job card, the parts fitted and the invoice. A folder containing a sales total will not answer that call.

The sensible aim is to preserve a usable archive, agree what can enter the new system, and keep today’s work moving. Here is how to organise that change.

What you keep, and what you might lose

Start with three different questions: can you retain the records, can you search them, and can you reproduce the old reports?

Do not accept a single “yes, we can import” as the answer to all three.

You risk losing convenient access if the only copy remains behind a login you can no longer use. You risk losing context if a job card arrives without its vehicle reference. A sales export without line items may preserve revenue totals while leaving you unable to identify the parts fitted.

None of that means the switch must destroy the history. Make each item an acceptance check. Preserve original documents even where selected information is also brought into the replacement system.

For reporting, save the old reports with their date ranges and filters. If you compare labour sales before and after the switch, write down whether each figure includes credits, discounts and VAT. Otherwise, a difference may send you looking for missing sales when you are comparing different definitions.

Export before you cancel the old contract

Cancelling first puts your archive behind an unanswered question: what access will remain?

Ask the current provider, in writing, when access ends, which exports are available, whether attachments are included, and whether read-only access has a separate charge. Check the notice period and the account deletion arrangements. Do not assume the answers from another service apply to yours.

Then make your first export while the account is active. Open the files yourself. Search for a familiar customer and an older job. Ask your accountant to check the financial records they will need.

Your pre-cancellation pack should contain:

• Customer and vehicle lists, with their original reference numbers.
• Job cards, including completed and open jobs, notes, parts and labour lines.
• Sales invoices, credit notes, payment records and outstanding balances.
• Parts records and, where used, stock movements and a dated stock snapshot.
• MOT dates recorded in your system, with the meaning of each date identified.
• Attachments, relevant authorisations and reports needed to interpret the records.

Keep a list of what each file contains and when it was exported. Save an untouched original and work on a copy. Store a protected backup separately, then check that someone authorised can retrieve it.

Set the cancellation decision against completed checks, rather than the day you first create a new account. The old service should not be your only route to evidence once that decision is made.

Ask for CSVs, with the links between records intact

Request CSV files for structured data. Ask for a field guide as well: what each column means, how dates are written, and which references connect the files.

A customer name alone is a weak matching rule. Ask to retain customer, vehicle, job and invoice identifiers. In your working copy, map these references before changing column names or removing duplicates.

The fields that matter in a garage

For customers, request the customer reference, name, contact details and invoicing address. Keep business customer details where relevant. Review the purpose of any extra personal information before copying it into the new working database.

For vehicles, request the vehicle reference, linked customer reference, VRM, make, model and VIN where recorded. Preserve previous reg information if you have it. Include mileage with the date it was recorded.

For job cards, request the original job number, vehicle reference, customer reference, opened and completed dates, status, reported fault, work completed and technician notes. Include authorisations where available. A row saying “service” is a poor substitute for the original detail.

For parts and labour, request the linked job number, part description, part number, quantity, labour description, hours, selling values and discounts. Include recorded cost values if you need them for later analysis. Mark whether monetary fields contain VAT.

For MOT information, distinguish the test date from the expiry or due date. Preserve the source and date of the information where recorded. Do not fill an empty field with a guessed date simply to make an import pass.

For sales, request invoice numbers and dates, linked jobs, net values, VAT, totals, credits, payments and balances. Keep original invoice copies alongside the structured export. A new customer database is not your complete sales archive.

Check the files before anyone imports them

Review ambiguous dates such as 03/04/2026. Confirm whether that means 3 April. Check VRMs, phone numbers and part references for unwanted changes in a spreadsheet. Leave the original export untouched.

Pick a small test set: an old customer, a vehicle with several visits, a job with multiple parts, an unpaid invoice and a credit. Follow each record across the files. Can you get from the customer to the vehicle, the job and the invoice without guessing?

Use that test to expose missing links before you spend time tidying thousands of rows.

How long should a UK garage keep the old records?

Do not apply one disposal date to every record. Your tax position and the purpose of the information matter.

For a VAT-registered garage, GOV.UK guidance on keeping VAT records sets the general requirement at at least six years, and it also requires copies of all invoices you issue. The OSS and MOSS schemes carry a ten-year rule, so check your position if either applies. The VAT rules that cost garages money day to day — the MOT fee, the simplified invoice and the nine items a full invoice needs — are in our guide to VAT for UK garages.

For a self-employed owner, GOV.UK’s rule on how long to keep your records is at least five years after the 31 January submission deadline for the relevant tax year. There is a separate rule for very late returns; check it if that describes your situation.

These periods have different starting points. Neither means “delete everything five or six years after changing software”. Where several duties apply, plan to meet them all. If you operate through a company, ask your accountant to confirm the applicable company and tax record requirements too. Agree dates for each record category before closing access.

Do not treat a financial retention requirement as permission to retain every customer detail forever. The data protection principles summarised on GOV.UK require personal data to be used for specified, explicit purposes and kept for no longer than is necessary. No single fixed period covers every record. Set a review date for the archive and restrict access to people who need it.

Keep required records complete and retrievable. Have your accountant check whether the proposed archive preserves the required detail and format. A collection of summary PDFs should not be assumed to replace every underlying record.

Move the work without stopping the workshop

Plan a controlled overlap between systems. Its length should follow your tests and contract terms; it is not a promised import timetable.

Start with tomorrow’s work

Practise with a test job before using the replacement for live work. Check customer entry, finding the vehicle by reg, parts, labour and the finished document. Let the person who normally handles the desk run the test.

Prioritise the records needed for incoming vehicles and current customers. Agree which history must be searchable immediately and which can remain in the archive. You do not need to recreate every old report before writing the first new job card.

For open jobs, choose a clear rule. You might finish existing jobs in the old system and start new arrivals in the replacement. If you transfer an open job, record the old reference and check parts, authorisations, deposits and remaining balances.

Choose one place for each live transaction

Write down the cut-off date and time. Tell the team where to create new jobs, where to record payments against older invoices, and where to look up earlier work.

Avoid asking everyone to maintain two complete live records indefinitely. That leaves you reconciling two versions of the same job. During overlap, assign one person to track exceptions and confirm where each transaction belongs.

Keep a simple fallback job sheet for an unexpected problem. Include the customer, VRM, fault, authorisation, parts and labour. Decide who will enter it afterwards and check that it has not already been entered.

Reconcile before ending the overlap

Compare counts and a sample of detailed records. Check customer-to-vehicle links, completed jobs, invoice totals, credits and outstanding balances. Test older records as well as last week’s work.

Check stock quantities and valuation separately if those records are part of the change. Note any transactions made after the first export. Arrange a final export or another agreed way to capture that gap.

Ask someone other than the person who prepared the files to find a past repair. If they cannot retrieve it, improve the index before calling the archive finished.

What Garage can consider importing

Garage can consider importing customers, vehicles and history from CSV files that you provide, following a technical review of those files. You export the files from your current system and supply them for assessment. The team then confirms what can be brought across.

That review must happen before you rely on a particular record or field being available in Garage. Do not assume every attachment, historical report or relationship will transfer. The outcome depends on the files and the technical assessment. Keep records outside the agreed scope in your independent archive.

Prepare a file list, field descriptions and the records that matter most to your daily work. Agree a secure way to provide the files. Keep your independent archive and current access until the agreed checks are complete.

You can use the trial to assess your future daily workflow while the suitability of your CSVs is being established. Testing the software and confirming the import scope are separate decisions.

If your history is in Excel or a notebook

Use the same order: preserve, organise, test, then change the live process.

For Excel, keep an original copy of each workbook, including sheets used for calculations. Prepare separate CSV copies for assessment. Document how a customer row links to a vehicle and a past job.

For paper records, retain the originals according to your agreed retention plan. Create an index of customers, VRMs, job dates and file locations. If you scan pages, check legibility and give each scan a useful reference. Digitising every page need not be the first task.

Begin structured entry with the customers and vehicles needed for current work. Mark any manually entered historical summary as a summary and keep its source reference. Do not present a reconstructed note as the original job card.

Your final check before cancelling

Can you find an older job by reg? Open the original invoice? Explain an outstanding balance? Retrieve the backup without the old login? Identify the work created since your first export?

If any answer is uncertain, resolve it before cancellation. You are ready to switch when today’s work has a clear home and yesterday’s evidence remains usable. If the replacement is still undecided, our buying guide for a small UK garage lists the tests to run during the trial.

Checked against GOV.UK guidance in November 2026. Retention periods, thresholds and data protection duties change, and they depend on how your business is set up — confirm your own position with your accountant before you dispose of anything. This is general information, not tax or legal advice.