In this guide 6 sections
Buy one product when both trades must share a single invoice, a single stock count and a single ledger. Buy two linked products when each trade keeps its own stock, billing rules and staff, and only the customer record crosses over; test those three meeting points first.
Start with the three places the trades must meet
Write down the invoice, the stock count and the ledger; those three are the only places where the trades truly collide. Appointment screens and job cards belong to one side alone. Everything else can differ.
Ask where a customer pays once for work done by both sides. A patient leaving with a consultation and a strip of tablets expects one counter. A driver who books an alignment with four new tyres expects a single bill.
Then look at shared items. Engine oil poured in the workshop and sold over the counter is one stock line with two exits. Split it across two registers and both counts drift apart within a month.
- One invoice for a visit that touches both trades
- One stock line drawn down by both trades
- One cash drawer or two
- One ledger, or two profit centres inside it
- Shared customer history across the counters
When one product stretched over both trades works
A single product suits you when the trades are small and the staff overlap. The receptionist at a showroom with a workshop books the service slot, sells the floor mats and takes the deposit for the next visit. One login. One day-end. One drawer to count.
Stretching has a cost. A garage product with a pharmacy tab usually treats tablets as spare parts, with no batch number, no expiry date and no schedule register. A clinic product with a tyre list has no wheel size, no tread depth and no fitment record; test the weaker side first.
Have the vendor key in one real sale on that weaker trade while you watch. Use a strip of tablets with a batch and an expiry date, or a tyre with a size and a DOT code; note where it breaks. That single test saves months of regret.
When two linked products serve you better
Two products fit when each trade has its own regulator, its own staff and its own month-end. A clinic lab runs sample IDs, reference ranges and a signed report, while the pharmacy beside it runs batches, expiry dates and a controlled drug register. Neither wants the other’s screens. Forcing them together helps nobody.
The link stays narrow. Agree which system owns the customer record, because two owners will give you two phone numbers and two spellings for the same person before the first year is out.
Ask how the link works. A nightly file, a shared database and a live connection each fail differently. A nightly file is simple, but this morning’s sale stays invisible at the other counter until tomorrow; know that before you buy.
- Customer master owned by one system only
- A visit or job reference carried into both
- A summary invoice line posted to the main ledger
- A named person who clears mismatches each morning
Test the shortlist with three real bills
Take three paid bills from last month: one from each trade and one that mixes both. Ask each vendor to rebuild them in a demo with your tax lines, your discounts and your print layout; if the mixed bill fails, move on.
Then run a stock test. Pick one item that both sides touch, set an opening quantity, sell some from each side and compare the closing figure with the shelf; it takes ten minutes. It tells you more than an hour of slides.
Last, open the day-end report. It should show each trade’s takings apart, with the cash drawer as one total that the cashier can count the notes against.
Decide, then write the boundary down
Once you choose, record the boundary on one page. Say which system owns the customer, which owns each stock line, and which produces the ledger entries that your accountant reads at month-end.
Review it after the first close. Compare each trade’s profit with your old register, and if the figures differ, find the line causing it now, before a workaround hardens into habit. The second quarter is too late.
This week, take last month’s mixed bill to the first vendor on your list. Make them rebuild it live.
Two-trade decision sheet
One page, five rows: invoice, stock, ledger, cash drawer and customer record. Columns read shared or separate, evidence from last month’s bills, which product handles it, and the gap. The foot of the page lists the three test bills, with the vendor’s result noted beside each one.
Open a blank worksheet to printQuestions owners ask
Can one customer record serve a clinic and its pharmacy?
Yes, and it usually should. One person keeps one phone number and one history; the care lies in deciding which system owns the record, so that edits flow one way only.
Is it cheaper to buy one product for both trades?
Not always. A single product can save a second licence but cost you in workarounds on the weaker trade. Judge it by the mixed bill test and not by the quote you receive.
What if our two trades have different tax rules?
Then the invoice formats and tax lines must be proven for each trade separately, live on screen; your accountant should confirm them; the vendor’s word is not enough.
Can we start with one product and split later?
You can, if customers and stock lines carry clean codes from the start. Export both masters on day one, so a later split does not mean re-keying thousands of rows.