"Approach to" or "approach for"

approach to NOUN

When used as a verb, 'approach' takes no preposition. However, when as a noun, it requires a preposition, otherwise you end up with two nouns in a row: "The pilot's approach [ ] the runway was too low." The question is which preposition is most appropriate.

Using the more literal example I gave above, it's easy to see why 'to' is more appropriate than 'for', and this still holds for more abstract uses:

"my approach to the problem"

"an iterative approach to the travelling salesman problem"

Oh good grief — this person is trying to use "approach to" or "approach for" as a noun, folks. It's a valid question.

• What is your approach to teaching English?
• What is your approach for teaching English?

I think both are correct, but the former sounds more natural to me.

I'm sorry, but Charles Goodwin is right. The "approach" itself doesn't take a preposition at all.

I'm approaching you.

Obviously, if I'm approaching you for a reason or to get some results has nothing to do with the approaching itself.

I might just as well use another verb and the situation would be the same:

I'm approaching you for a reason.
I'm flattering you for a reason.

and:

I'm approaching you to get some results.
I'm flattering you to get some results.

Please observe how for introduces a noun (a reason) and to introduces a verb (to get). That's why in some cases you should use for and in others you should use to.

Now the catch with the caching is that it can be both a noun (the caching) and a verb (to cache as the gerundive mood). So obviously both forms are correct!

Happy caching, don't forget to invalidate often and have fresh data for your users :)

It sounds like you inadvertently are conflating the verb "approach" with the usage of verbs attached to the other subjects of the sentence.

In trying to come up with use cases for both:

Shall I approach for advice [from him]

Maybe I will approach to get an answer

I lack the technical knowledge to describe it more correctly, hopefully somebody else will elaborate.