The instructions may recommend preheating, but with the two air fryers that I’ve had in my life, for both of them I found myself taking off last minute or two because it tends to overcook. Doesn’t matter if it’s anecdotal, directions are words on paper and they can’t understand the reality of the rules they set.

The people who write directions aren’t thinking of use, they’re thinking of legal consequences. Any company that makes an air fryer would rather have you burn your food than eat it undercooked.

As an honest answer, no preheat time. But I have an air fryer-pressure cooker combo, so the air fry is more of a bonus. If you already have a connvection oven, yeah there’s absolutely no reason to get an air fryer.