It depends on what you mean by leftovers. I have some fabrics that I bought specifically for a project. On some of these I have 'scraps' leftover. Some others I have 'yardage' leftover (fat quarter or greater). I have recently begun saving pieces left after trimming during paper piecing.
I tried to make a 'scrappy' quilt using only my stash. I picked 4 colors - purple, aqua, orange and neutrals. I then started to make the blocks and realized that my neutrals and oranges all looked too similar in value/scale/color to qualify as scrappy. So I purchased approximately 10 - 1/2 yard pieces of both neutrals and oranges to enhanced the 'scrap' factor of the quilt. I love the results but it certainly did not reduce my stash. LOL!
I find myself using my stash as a starting point for projects and then adding to it to complete. And the 'leftovers' continue to grow. Right now I think my stash is larger than my leftovers (but probably not for long).