One size discipline: carrying fewer spares across a fleet
Every fitment page lists the other vehicles that run the same size. Read the other way round, that is a stocking decision: one spare on the shelf can serve four vehicles instead of one, and the shelf is where a small fleet quietly loses money.
The fleet desk can do this for your own vehicles. Its ledger says how many different sizes your fleet actually runs, and which single swap at the next replacement would simplify the stock most.
The discipline pays twice. Fewer sizes means fewer spares standing idle, and a larger order of one size buys better than four small orders of four. It is worth checking before the next set of tyres, not after.