I drill three good-sized holes around the underside of the bottom edge, and one in the center...usually. I make fewer holes for bog type plants.
The ones I like the best are 8" wide by 14" tall. They can be a bit harder to find. I especially like these for shrubs grown from seed or purchased small. I've had some seed started shrubs in these for three years now and they're still happy.
The liners shown in the pix above are 10" wide, by 12" tall.
