do wallet.dats include future addresses?

[ehmdjii]

if i backup my wallet, will future addresses be included?

or do i need to make a new backup each time i create a new address?

[CIYAM]

Your wallet contains a "key pool" which by default is 100 addresses in length (this can be modified in the config file if more are wanted).

Thus you only need to make a new backup every now and then (depending upon how many addresses you are using). Understand also that normally when you send coins a hidden "change" address is created to return change to yourself and these hidden change addresses are also taken from the same key pool.

In particular note that if you have not yet encrypted your wallet then you will need to create a new backup immediately after doing so (as the keypool addresses are discarded and new ones created after encryption).