What is the difference between a carnauba wax and a synthetic sealant?

A carnauba wax is a natural wax that characteristically beads water and gives a warm, deep gloss, but it attracts dirt more readily and has less detergent resistance than a synthetic product. A synthetic sealant sheets water more than it beads, has better self-cleaning properties because its lower-energy surface repels contamination, and lasts longer between applications because detergent cannot emulsify it as easily as it can an oil-based wax.

Does leaving a paste wax to cure longer than the label says improve protection?

For waxes, yes. A 24-hour cure produces a meaningfully more durable result than the typical 10-minute label instruction. The trade-off is that a wax cured that long is harder to buff off, so apply a thin layer. For synthetic sealants the gain is much smaller, roughly 5%, so following the manufacturer instructions is fine without extending the wait.

Is it worth applying two coats of wax?

Two coats of wax or a polymer sealant, with a 3-hour wait between them, produces noticeably better durability than a single coat. In controlled wash-pass testing the two-coat sections held hydrophobicity roughly 20% longer. It is worth doing on a freshly prepared car where you want to get the most from the protection. Less critical if you plan to re-apply in a few weeks anyway.

When should I choose a paste wax over a spray sealant?

Reach for a paste wax when visual appearance matters more than convenience. A properly applied and cured paste wax produces a warm, reflective finish, sometimes described as a jetting effect where light turns to colour across curved panels, that many people find more noticeable than the look from a synthetic sealant. If you want maximum durability or self-cleaning behaviour on a daily driver, a synthetic sealant or ceramic spray sealant is a more practical choice.