I've used a lot of different waxes over the years, but the last couple years I've been using a Meguiar's spray wax. Definitely use a clay bar first on paint that still has its shine. Faded/oxidized/stained will need compounding first. The spray wax lasts months outside, easy to apply. The ceramic sounds longer-lasting but I haven't tried it yet. Here's a winter pic of my trusty '93 Pathfinder, mostly original paint, 209,000 miles.