I find the time varies, and that the amount of attentiveness required is much lower than that for FSD. FSD will ding you very quickly if you have a device in your hand, especially compared to plain autopilot.

My car came with an internal camera that didn’t have IR lights, which made FSD completely unusable at night time (they put in a new one under warranty).

I only subscribe FSD every few months for long trips, but I have a 1400 mile road trip planned this weekend and I will be using plain autopilot.