Trying many ROMs ... Should I switch to stock ROM every time in between?

[tichi]

Hello guys, I finally decided to take the plunge and to screw my Touch
with GPS and other goodies.. However I expect to try at least several different ROMs, like NFSFAN's, ghettofreeryders, etc..

I have very dumb question...
Should I repeat everything starting from the verse # ONE of the Bible:

(: UPDATED- CONSOLIDATED Rev A./GPS TUTORIAL - look here before
asking questions.) )

every time between

flashing different ROMs,

or it is sufficient to
repeat only the verse # 13?