PURPOSE: FOR AND TO

	FOR or TO + infinitive: INDIVIDUAL PURPOSE For is commonly used with nouns to express individual purpose: I popped into the supermarket for some apples on the way home. (Not: I popped into the supermarket for buying some apples…) I stopped by at his office for a chat about our marketing strategy. (Not: I stopped by at his office for having a chat about marketing.) I decided I would save up for a new computer. (NOT: I decided I would save up for buying a new computer.) If we want to express individual purpose with a verb pattern, we are obliged to use to + infinitive: I stopped by at the supermarket to buy some apples on the way home. I popped into his office to have a chat about our marketing policy. I decided to save up to buy a new computer.
	For + verb-ing: the purpose of an object However, if we are talking about the purpose of an object or an action, we normally use the for + verb-ing pattern. Note that this pattern commonly answers the question: What are they (used) for? Compare the following: Schools are for educating children not for entertaining them. Schools are for learning. Life is for living. This kitchen knife is especially useful for slicing vegetables. What's this for? ~ It's for opening oysters. It's much better than a knife. What's this fifty pound note for? ~ It's for buying food for the weekend. Note that when the subject of the sentence is a person rather than the thing described, the to + infinitive pattern is also possible: I use this small knife to slice vegetables with. I use this gadget to open shellfish with.