Do you leave your platter spinning while switching

It was always the done thing with LP12s - largely due to the low torque arrangement. It helped stability to leave it on. The Hercules II is even worse! (Bit of a misnomer that...)
The felt mat had a constant tendency to attach itself to the LP during flipping and occasionally dropped off during the act, causing it to assume a dangerously wide arc towards the stylus! (Another reason for preferring a Ringmat :) I never damaged a cartridge despite this.

So I continued that practice for 25 years until I acquired a Raven, which I always switch on and off as the platter size doesn't lend itself easily to "active flipping".
The Raven's platter is always stabilised in < 1 second so there's no hardship in doing this. If I was going to give it a helping hand I'd have to be quick!!

YES........ I leave my platter spinning when I turn over an LP or put on a new LP. No magical manual dexterity,.. just simple care and an easy touch.

I use a TW deck too, the Raven one and leave it spinning. I don't use a clamp. I tried a Shun Mook weight and could'nt detect much difference. That being the case, it is easy to take a disc off a spinning platter and I agree that constant turning on and off, would logically seem to add stress to the motor and controller.

no, i use a TTWeights outer ring weight. The platter must be stopped.

I never turn off the TT when changing LP's.

I also never shut off my belt driven turntable. It runs 24/7 and my theory is that it won't develop a spot on the belt if left in the off position for a day or two.

When I used to shut off the TT, I had a chance to removed the belt after about two weeks of non-use and I found the part of the belt that wrapped around the drive pulley developed an "image" of the drive pulley on the radius of the belt.