i guess you've got to if you want up-to-date package repositories. that's one thing that's handy about a rolling release..
i've been getting curious to try out gentoo again when they do their next release (2007.1, which i think will be late november), but i keep trying to tell myself it won't be worth the headaches. i really have no problems in arch, and if i can exercise some will-power and resist the urge to tinker with other stuff i don't think i'd have to do a fresh install ever again. i guess when everything "just works" i get bored, lol.