I don't rep noobs. Period. I go through occasionally and make a list of people to rep, and spend some time composing the comments, then rep a bunch all in one pass. Unfortunately, sometimes I miss people that way (CD and Kayenneh being unfortunate 'victims' of my method.)
It would be nice if there were better tools for managing giving rep to people, but if there are, I'm unfamiliar with them. One change I would like to see, though, is the addition of a separate field besides the comment for "favorite post" (or posts) of the member, autofilled if repping from a special, post context, rep button ("Give rep and* cite this post.")
Now that I've repped quite a few people, my fuzzy brain has trouble remembering who I have and have not repped.