I would like a long lasting floor covering with no seams (because seams tend to get dirty). Most of the vinyl tile I see sold by Sears and Home Depot are self-stick. Do self-stick last over the years as well as adhesive?
If you want "no seams" then you don't want tiles, period. That's what sheet vinyl flooring (often still misnomered as linoleum, though actual linoleum is quite, quite rare these days) is good for, if the space to be covered is less than 12 feet in one dimension (after that, you're stuck with a seam.) It actually has no seams (if the 12 foot limit is not exceeded - 12 by whatever is fine, as it comes on a long roll, 12 feet wide.)
I have self-stick tile in several spaces - basically low-traffic closets, and it seems fine in those on its own adhesive, applied with care to a very carefully cleaned floor. If you are breaking out the tile adhesive, might as well break out the commercial-grade vinyl tile (made with no stickum) it's made to go with, which is a far better tile at not much more cost. The difference should be obvious comparing the two types - HD typically carries one, perhaps two colors of commercial vinyl (all the others are "order and they'll get it"), and it's a much thicker, more solid vinyl than the thin stick-ons. It's basically all wear surface until you wear right through it, while the stick-on starts thinner and has a much thinner wear layer.
A third possibility is an epoxy coating, with or without "color chips."
It seems the only time self-adhesive tiles will stick is when one wants to remove them. And, in those cases, we've kept track of what was holding them down:
1) Troweled (evenly spread) flooring adhesive
2) Luan plywood underlayment (often with evenly spread flooring adhesive)
I've been told (numerous times) the key to laying them is to warm them up (ie. hair dryer, microwave oven, hot water).
I did help a guy install self-adhesive tiles, using flooring adhesive over B-C plywood, in which the tiles were warm from being in a hot van. Yes, the warmth did seem to make the self-adhesive on the tile more sticky and the tiles weren't so stiff; making it more effective to use a roller to press the tile into the floor adhesive we used. If we were using luan we would have skipped the floor adhesive (maybe).
One guy said a coat of paint primer, sticky to the touch, will seal the plywood and create additional "sticky" for the tile. We all imagined tiles coming up with splotches of primer stuck to the back of the tile. The jury is still out on this idea.