What canvas size do you usually work on?

What canvas size do you usually work on?

I usually work at 8.5 x 11 inches (letter size) or 11 x 17 inches/12 x 18 inches for most actual full pieces. There basic and well composed sizes that are also usually available at most printing places. c:

There’s probably others that are equally or are more effective and I do use other ones but those are the probably the ones I use the most.