That's a mis-conception about the auto hubs, they are engaged when the front drive shaft applies pressure to the hub via the axleshaft, not from the wheels turning. They do take 1/8 of a turn or less before they'll click in, and when they do pop into place, this is what usually causes the most wear. Very common for them to wear out inside without knowing it. The internals just aren't built nearly as well as manual hubs.
I had auto's on my Bronco, 5-screws on the caps, no conversion kit needed. The 3-screw caps generally need the conversion, the 5-screws usually do not, at least that's how it is on the Broncos. What it boils down to is the locknuts on the front hub, the manual hubs require 2 lock nuts, and if you have the self-locking single setup, you need to replace it with the locking nut.
When I pulled my auto hubs off the Bronco to do the brakes, the pasenger side came out in about 10 pieces, and when I found out they are about $260 each side for new ones, the $90 I spent for the pair of Warn Premiums was a no-brainer. I just had to train my wife how to use them. They are definitely stronger than the auto hubs, just not as convienent. I just lock the hubs when I think I might need them, and use 4WD as needed.