1. Cutting is the business, not a service
Almost nothing leaves a glass shop uncut, which means your cutting table, your tools and the skill of whoever uses them determine both your speed and your wastage. Budget for a proper table and good cutters rather than the cheapest available, because a bad cut is a full sheet lost. The person who cuts is the most important hire in the shop.
2. Thickness and type are separate items
A 4mm plain sheet, a 5mm, a 12mm toughened, a laminated sheet and a mirror are entirely different products at very different rates, all sold by the square foot. Entering them generically guarantees wrong rates and a meaningless stock figure. Keeping type and thickness on the item also means the bill says exactly what was supplied, which matters when a customer compares your quote with another shop.
3. Breakage is a running cost to measure
Glass breaks in handling, in cutting and in transit, and in most shops that loss is absorbed and never counted. Recording it as a stock adjustment with the reason turns it into a monthly percentage you can act on — and once visible it usually points at one thickness, one supplier or one delivery practice rather than at general bad luck. In a trade with these margins, a couple of percentage points matters.
4. Charge for the work separately
Cutting to size, edge polishing, drilling and fitting at the customer's premises are separate services with their own margins. Hiding them inside a per-square-foot rate makes your material look expensive while your labour looks free. On their own lines the customer sees what they are paying for, and you can tell monthly whether the fitting work is actually earning what you assume.
5. Site fitting and its risks
Fitting work at a customer's premises brings two things: better margin, and liability if something breaks during or after installation. Record what was supplied and fitted, on what date, and get an acknowledgement. A delivery and fitting record with the receiver's name is what settles the conversation when a panel cracks a week later and the cause is disputed.
6. What to stock first
The two or three thicknesses of plain glass that carry most local work, mirror in the common sizes, and one toughened option if your market asks for it. Toughened is made to order in most cases rather than stocked. Add depth where customers repeatedly want something you did not have. Glass is bulky, fragile and expensive to hold, so wide stock is a costly way to learn what sells.