I've tried different widths. Currently I stick with 2.5, because then what ever is left over I can easily cut into 2.5" squares for my scrap drawer.

I use 2.75" with about 3/8" seam allowance unless the design or batting calls for a narrower width. That size works well with my walking foot and the batting fills the binding nicely. With each quilt I sew about 10" with that seam allowance and then test that the binding turns over, fills the batting, and ends up right at the stitching on the back. Then, if necessary, I adjust the seam allowance accordingly.

I ususally use 2 1/2" on wall hangings about 2 1/4"

I cut my binding 2 1/4" for machine binding, I am ok with 2inches also, especially if I am doing a hand binding.

2" for me ....

Generally, I use 2 1/4" now. I used to use 2-1/2", but switched. I may still use 2-1/2" for a quilt with a double batt, not sure, but I did one recently and it seemed like it was a bit of a stretch with the extra layer of batting.

2 1/4 works best for me. Nice thin binding.

I use 2 1/2" for binding a large quilt and 2 1/4" for table runners and wall hanging.

As a newbie I did 2 1/2" but have long since switched to 2 1/4".