I do both. If it is a quilt to be entered for competition, it needs to be bound by hand. If it is a quilt that I have spent loads of time and effort piecing and quilting, I hand bind those as well. But if it is one that I make for the grandkids that gets drug about and washed often...I double the binding and machine bind. I also offer binding to my customers and 80% of what I do is by machine (probably because it is cheaper). I always ask how it will be used and then ask if they prefer single or doubled binding.