Chances are your business owns a number of vehicles, computers, printers, and assorted other equipment if you perform services. You should have some way of tracking the assets and their associated maintenance and repair costs on a unit-by-unit basis. It's unlikely you or someone else in the business will be able to track them mentally. Increasing repair costs can be a strong indication equipment is coming to the end of its useful life, or you've just got a lemon that will continue to suck cash. You can start with a spreadsheet listing the purchase date, identifying the equipment, and then listing the repairs or maintenance costs, along with a brief description of work performed. It'll give you a better idea of which units or models are racking up the costs.