I don't use QT, I use Multibit.
multibit doesn't use wallet.dat. they uses .wallet format and .info for description and labels. that's what you need to copy.
Si once I have backed up a copy I don't need to back up again unless I add additional funds, right?
you don't need to back up unless you generated a new address. but to be safe you can do that every time you like.
And if I later wanted to import the wallet back into Multibit do I import private keys or is there another way to import a wallet?
Can you import a wallet on top of another one?
Srry for all the questions.
the
back up wallet is to be used when something went wrong with your primary wallet. you can import private keys but you can't import a wallet on top of another.
use the edit button instead of triple posting if you don't want to be warned by a mod.
