I have a big, detailed want list of sets I am collecting--those are the gotta have it items.
I have a big list of issues that I collect where I am unsure as to whether my want list is complete. Anything not checklisted is something I gotta have too.
I am always looking for oddball types that I don't already have or haven't seen before. Collecting is a continual learning curve, which is part of the fun.
I will always look at certain issues where I think I have an expertise
looking for variations that might go unnoticed or bargains I can stockpile as trade bait.
I will always look at good flipping material too.