The number to watch
Breakage as a percentage of purchases. Every glass shop loses stock in handling, cutting and transport, and almost none of them know whether that loss is two per cent or eight. Once breakage is recorded as a stock adjustment with a reason rather than absorbed silently, the monthly figure tells you something actionable — whether a particular thickness, a particular supplier or a particular delivery route is costing more than it should. That is a margin conversation, not a housekeeping one.
Area billing with thickness on the item
A 4mm sheet and a 12mm toughened sheet are different products at very different rates, and both are sold by the square foot. Keeping thickness and type as part of the item — plain, toughened, laminated, frosted, mirror — means the rate is right without anyone remembering it, and the bill says exactly what was supplied. That specificity is what prevents the argument when a customer compares your quote against another shop.
Cutting, polishing and fitting as their own lines
The glass is only part of what you charge for. Cutting to size, edge polishing, drilling, and fitting at the customer's premises are separate services with their own margins, and hiding them inside the rate per square foot makes your price look higher than it is while your labour looks free. Putting them on their own lines is both clearer for the customer and honest about where your money is made.
Breakage is a real cost, not an accident
Every glass shop loses stock to breakage in handling, cutting and transport, and in most shops that loss is never recorded anywhere. A stock adjustment with the reason noted turns it into a number you can look at monthly. Once it is visible, you can see whether a particular thickness, a particular supplier or a particular delivery route is costing you more than it should — which is impossible when breakage is simply absorbed.