| this is the only one of your questions that didn't send me in to a laughing fit... it kind of depends on your skin texture and temperment. I don't need a lip primer, myself. never had a problem with bleeding or feathering, and honestly, I PREFER stuff that wear off over the course of the day- the stains and inks and 'long wear' stuff tends to look unnatural to me. don't need a foundation primer, either- I don't wear foundation, so it's a moot issue. I DO, however, own and use an eyeshadow primer, and a fancy 'concealer' brush to apply it with. it does indeed work like a charm under powders and creams. keeps eyeliner from migratine, powders from slipping into the crease of your eyelid- I don't use it often, only when faced with photographers (formal parties, interviews) or adverse conditions (sometimes, even the old hippy needs to dress up in summertime ;) a tube (I get mine from Beauticontrol, through a dealer, but they're all mostly the same general formula, think covergirl makes a fine one) lasts me longer than you're supposed to keep makeup, partly because I use the brush to apply it (also keeps it from getting icky) | 
