One of my greatest frustrations with vinyl shopping is finding something that looks like a great find, then wondering: is it available on cd? has it been remastered/re-released? is it worth the sale price? is it a bootleg? if so, what is the quality? I realize a vinyl purist doesn't care if it's a cd release or not.
I've always maintained a "to get" list of some sort. Lately I've tried to cull out the material I want that is only available on vinyl or that is prohibitively expensive on cd. I keep the list on a PDA I carry so if I find myself in a vinyl store spontaneously I'll know what I'm looking for. So, my buying approach is to search for all those bands in my list, first and foremost. If I can't find any of them I usually go home empty-handed. This "planned" approach to collecting is limiting that way and can be frustrating. Some stores have terminals to access AMG - but most do not.
I'm curious what other vinyl collectors do - are you proactive and deliberate in what you search for or are you more spontaneous and risk-taking? Do you prefer retail stores or Ebay? How do you make sure you're getting something worthwhile? Do you keep lists or do you go by memory?