We resurrect threads fairly regular like around here. No worries.
I train in what I'm wearing when I find the time to do it. Shoes, boots, slippers, socks, bare feet, flippers...
OK, never in flippers. Sounds fun though.
In the Spring I was wearing Converse skate shoes but I've changed over to deck shoes as summer has come on.
I also train in everything from parkas, to three piece suits, to shorts and a T, to sweat pants, to my birthday suit (when I'm alone, obviously), as well as any other type of gear you can think of (now I'm picturing myself doing TCC in full scuba gear, but I digress).
When I teach I try to present a professional front so I wear comfortable pants and either an ETC shirt or an IYFTCCA shirt, whichever is clean and handy when I'm heading to my studio, and usually a pair of tennis shoes of some kind.
I simply wear what's comfortable/what I have on/what is appropriate for the moment, as required.