Revenue categories split income by the kind of work that produced it: service, installation, projects, maintenance agreements, retail, add-ons.
Why one revenue number is not enough
Total revenue tells you the size of the business. It cannot tell you which work is worth doing, and those are different questions with different answers.
A month at the same total can be a good month or a bad one depending on what it was made of — high-margin service work and low-margin installations look identical in a single figure.
The categories worth separating
Split where the economics differ, not where the work feels different.
Service against installation — different margins, different labour intensity, different cash timing.
Recurring against one-off — see recurring revenue. Predictable income is worth more than the same amount of unpredictable income, and it should never be buried inside a general total.
Add-ons separately, so you can see whether they are actually happening. Add-on revenue that is not tracked is add-on revenue that quietly stops.
What it enables
Reading revenue by category next to cost by category is what produces margin by work type — see job margins, where the common finding is that the work filling the schedule is not the work carrying the profit.
Without the split, that finding is unavailable.
Keep it short
Five to eight categories is usually right. Twenty produces a report nobody reads and a categorisation decision nobody makes consistently — see chart of accounts.