Webmail vs client question

[Linux for blind general discussion]

So this came to mind earlier, and I'm wondering if I can do anything 
about it, and it was prompted by an idea I had to save disk space.


I've read up on the difference with POP3 vs IMAP, and I like how 
Seamonkey/Thunderbird/Claws/etc handle mail in a much easier to read 
format than webmail interfaces.

But I'm wondering if there's a middle ground, if I can have a client 
that lets me access my mail, but doesn't clutter up my disk? I was told 
both POP3 and IMAP eat up disk space on a computer after all, and I'm 
both not sure how true that is, and wondering if I can do anything to 
mitigate that?