When should a paint sealant be used? How is this different from other waxes?

CliffNotes® version

Sealant - a non-organic (synthetic) polymer is much more durable than an organic (natural) Carnauba wax.

Carnauba wax - provides a ‘warmer’ look; especially on dark coloured paint (very subjective) it also gives better protection against bird excrement and acid rain. Used as a sacrificial barrier that’s easily renewed

I usually combine a sealant and then use a Carnauba wax

Both paint sealants and waxes are ment to do the same thing which is to protect your paint from external elements that can damage it and to enhance it's looks.

Like TOGWT waxes are natural and paint sealants are synthetic. A lot of paint sealants make claims of lasting a long time but from experience I can tell you that not all of them do. There are also some great ones on the market that look good and last. Most are easy to use meaning they go on and wipe off easy. One draw back on a lot of paint sealants is their long cure times. Many require 12 hours of cure time between coats or before the paint gets wet which can be a drawback.

I also like to put on a paint sealant then apply a carnauba wax on top of it. If you use both always apply the paint sealant first because it won't bond well on top of a wax. It's hard to beat the warm glow of a carnauba wax on paint. I always use paint sealant on my wheels and brake calipers. From my experience they really hold up much better then a wax in those areas.

I've had great luck with Klasse All-in-One (a cleaner/polish with glaze) followed by multiple coats of Klasse High Gloss Sealant Glaze. Add another coat of the Glaze every few months, depending on how much you drive the car. Very long-lasting.