I can only remember cutting borders length of fabric for one quilt. It was called for in the pattern. It was one of the earliest quilts I made after I retired from work. I was so nervous about cutting into that beautiful fabric. And a funny thing, that is what lead me to this quilting board when I Googled how to cut borders length of fabric! Been here ever since!
Seriously, I don't think I have ever had to do that again. I piece my borders, usually with a mitered seam because I like that look. I agree with others who have said once the quilting is done, not noticeable, either way