[iBook] POP or IMAP?

[Pat]

I've been having problems with my iBook, G3 and had to pay $50 for help 
in getting it to work on both getting to the internet and receiving 
Mail...all because it's not my main computer and hadn't been used for a 
couple of months and had apparently lost it's mind.  AppleCare had run 
out in Dec., so I had to pay for advice.  We got it up and running, but 
it is set on IMAP rather than POP and I'm wondering what that will mean 
when I travel.  I thought it had to be set on POP.

Any thoughts?

Pat