I'm not at this - what do you do if you don't miter ?

Same here. I can get one side but not the other. Too frustrating.

I look at the fabric and I will only miter if the design in the fabric will look better. I think it's harder to get a flat border when you miter it so I always try to be real careful in measuring.

One of the easiest way to miter is to sew on all the borders stopping 1/4" from the corner and locking the stitch. Then play around with the corner folding the fabric to where you want it then ironing it down and I like to put a thin strip of double sided fusible there to hold it in place while I sew it. Some people will top stitch it down with invisible thread.

I don't like mitering. I try and make most of my quilts with the backs a few inches larger than the front so I have a built in binding. Does anyone else do this? Easiest way possible and the people I make quilts for wouldn't know the difference anyway.

I just learned how and its nice to have the option - once I figured out how to miter corners it was easy (although I haven't done it alot - probably depends on the quilt). I just do what I think will look good.

I like how mitered borders look, but by the time I get to the borders, I am anxious to finish the quilt. And since I don't usually miter, it takes me longer.

It depends on the pattern. I have mitered some, and gone straight on others. To me, using a mitered border is not wasteful because the leftovers go into the scrap bin for another day.

I have done both, but I prefer NOT to miter! Depends on the quilt, I guess.

It's a personal choice. I like the look especially if the fabric has a directional design.
What I do if there are more than 1 border is sew all the borders together as they will appear on the quilt. Then I sew them to the quilt and miter them all as a group instead of doing one border at a time. That way the angle is consistent through all the borders.

It is a method to finish the corners of your quilt. If you want more information, am sure there are a ton of websites with a tute.

P.S. Have never done it. By the time I get to the borders am "done"! :-)