I used to keep an excel spreadsheet detailing everything. stopped doing that. there's a thread somewhere on this site for software to track it.

when i buy boxes, i write a label on the box for aging, or when it drops to singles, use the bands or put them in a baggie and label it that way. otherwise, and unless i'm aging the sticks - i don't care to keep track. and i don't think sharpies are going to hurt the sticks - unless perhaps you're putting the labels in right after you write on them.

this is my .02, but i also hang my shirts from light to dark in the closet.