I read somewhere about stocking an item if you use it more than four times in a year. The more I practice this the profitable it becomes. Most clients are looking for alot more but only call you when they really need your services. Everyone has a "list" of itmes they would like to do but forget about it themselves or don't want to trouble you. It is nice when you can talk with them about the "list" and not only give them pricing but also finish the work without ever leaving the jobsite.