do i have to wash the base or use shampoo at all? because i think it will be a lot easier to know exactly where the unit needs to sit if i have it styled already. like is it fine if i just take off the tape and residue from the base and my head and then just reapply? or will there be scalp oils etc on the base that needs to be washed off with shampoo? i was thinking i can lightly clean the base so that the hair barely gets wet. anyone have any tips for this?

We all lose microscopic skin pieces from all over the body, including from the scalp, daily. Bacteria and other little `guys` live on /break down these. Your scalp also produces oils etc. even on bald heads.... all this material can/does accumulate under tape/glues....oils and sweat will be absorbed by lace... acids in sweat will weaken/damage any base materials over time, including poly. As a matter of hygiene / health you should give your lace a rinse each time you de-bond, otherwise you`ll risk [at the very least] unpleasant odours from a build-up of such material....just sit it in a sink of lukewarm water to which you`ve added some shampoo....give it a few minutes and rinse it off/dry it .... re-bond when the lace is totally dry.

Elvis:

I've said this before but I'll repeat it again for other's benefit.
1% of residue (be it glue, oil, moisture etc) equals 10% less adhesion on the next reattachment.
So apart from the hygiene, as mentioned by Paul, there are advantages to always ensuring the base & scalp are as clean & dry as possible.

follow bonding debonding tipps advice,
take no chances,anytime,its easier in the cooler months,
just make sure both surfaces are megga dry,clean,
and wash youre hands first prior to applying adhesives,to the scalp, as you dont want natural skin oils transfering to the glue,from youre finger tipps,
if youve done all the prep, and you still think youre scalps oily, then put a tiny amount of gentle shampoo on lather rinse, that should do the trick, spray on more alchol if you want to be sure.
but for a rock solid hold, the key is megga clean, megga dry
"its not luck its knowledge and prep"
it can be easier searching u tube for video, as its easier to see watch
hands on techniques rather than theory,
bit like driving, theory and practical are worlds apart

* they are both as important as each other*
*happy newyear to everyone here*2012*