Liquid waxes and sealants are easy to apply and buff off, add great shine, water beading and protection.  They are also a sacrificial layer that can be removed, they sit on top of the clear coat or glass, so water dirt and the environment come into contact wit the wax not the underlying clearcoat and paint.  If there is surface damage, water spots or etching that is on but not through the layer of wax or sealant, it is not only easier to remove and clean off as it is much smoother than paint, but also if needed the layer of wax or sealant can be removed with a wax and sealant stripping soap like Chemical Guys cleanslate and with it whatever is on or in the wax or sealant.  Then you can reapply fresh smooth and shiny wax or sealant.

Spray Waxes Sealants and SiO2 hybrids:

Are quick and easy to apply.  Many of the best spray waxes now have very comlicated chemistry, 

Sealants: 

Last typically 6-12 months 

The most durable Is Autostolz Enhanced Wax which has Carnauba wax and synthetic sealants to give great shine and durability, even to alkaline car wash soaps.  Autostolz conservatively claim it will last 6-9 months, but we find it will often last up to 12 months depending on conditions.  You apply by hand with a microfiber applicator, then once applied you can go back where you started and buff off. 

Chemical Guys Jetseal is similar, but pure synthetic without the shine of carnauba.  Durability is similar, "typically 6-9 months" and "up to 12 months" are the same in real life testing, and reflect marketing decisions of where to set expectations, push them high, or under promise and over deliver.

Liquid Waxes

Liquid Waxes Like Butter Wet Wax, Cherry Wax are similar, but last less, typically 2 months

Cleaner Waxes

Cleaner Waxes also include abrasives to clean light defects as you wax.