As mentioned, I'm at least on AP no 5. It has had less use than the previous units because I've played around with some other priming tools including the Safety Prime on my Classic Turret press. The current AP has the round tray, so I may be getting more mileage from of it from lubing it more frequently. Not that I didn't with a couple of its predecessors, just not as often and probably didn't lube the 1st much, if at all.
For me, one of the biggest safety issues has been when they've reached the limit of their usable lifespan they begin short-seating primers where a second strike on the primer will be needed to set it off.
It definitely pays to monitor primer seating depth.
And since one of my presses is the Classic Turret, I'd prefer to prime with it if there was a reliable priming tool. They've redesigned, supposedly, the original Safety Prime, but it remains to be all plastic, so far as I know. And because of plastic or other poor quality parts in the drive system of the CT, it lost the ability to auto index a long time ago. And again shortly thereafter the replacement parts. Over time I've found that manual indexing can be about as fast, and also allows some options for steps you might want to make along the way.