On Monday, April 23, 2018 at 10:06:32 PM UTC-4, wrote:

Oh, yes there is an exception. If an old microwave has no turntable, forget it, those ones are hopeless and a food poisoning risk.

My last two MWs have turntables, and they *still* require frequent dish movement to keep cooking more or less even. The turntable helps, but I spend as much time moving the dish as I did in my old Litton without a turntable.

Of course, even with a turntable, any thick casserole or soup dish requires constant stirring lest you want a scalding hot dish with an icy cold center (my brother calls that the Katherine Heigl effect....)