| Highly dependent upon the state. In my state the laws are so complex even the state can't give good, simple guidelines. I work on furniture. Labor and materials are taxable, based on the place where the work is done. However, if it is a built-in (cabinet, vanity, stair rail, it is considered real property and not taxable.) Getting a haircut is not taxable; getting a manicure is taxable. Buying spaghetti and noodles at the grocery store is not taxable; buying a bowl of take-out spaghetti is not taxable if consumed off-site; is taxable if you consume on-site. Fruit juice is not taxable; soft drinks are. On and on. Getting your driveway plowed is taxable; if your neighborhood teenager shovels it, it is not taxable as long as they don't do more than $500 business a year. | 
