It would be great to include an inventory system for parts used to offer services, as is the case of an auto shop, where the service may be air conditioning repair, but in order to provide that service the shop owner has to know which parts are used in the process, how many are in stock and how much each one costs. So that as they are used, they are discounted from the stock. This would help a lot because it allows us to know what the profit is when offering service X with a certain price, in which Y and Z parts with a certain cost were used.