I'm on my first 2 510 attys that I bought 4 months ago. Never clean them.
I've gone through plenty of batteries, but the attys keep going strong.
edit: an atty is the part that heats up to vaporize the juice. It's the part between the battery and the cartridge on a 3 piece (510, 801, 901, etc...), or inside the cartomizer on a 2 piece (808, etc...). Oh...atty is short for atomizer.
I have 3 or 4 510 atomizers I've been using since for the last 6 months... every now and then (every few weeks) i rinse 'em and blow em out with an air compressor. Then I dry burn 'em before I apply juice. None have failed. Go figger.