A scrap to small to use is anything that would not be big enough to piece together somehow. So if it can't at least fill in that little corner where I need just a bit more then it is not something I might at some point use. Guess that means under 3/4" as I use strips that narrow for piping and I've used some pretty tiny triangles in scrappy mug rugs.

I save anything 2 inches or bigger, and things that are somewhat yardage, I put on a board instead of the scrap bin. Trouble is, I seldom use those small pieces, so I just about consider that a waste of time and storage. I see so many videos on using 2 1/2 inch strips as scraps, but I never have any of those. I guess I haven't used a jelly roll yet, and that's where you get those scraps.

i consider a scrap what ever is left when i am finished with my quilt- unless i purchased extra yardage.
sometimes my scraps are foldable- sometimes they are small corners / squares/strips- sometimes i cut my scraps into the largest piece i can get out of them- sometimes the piece gets tossed into my (applique) tote
sometimes they get tossed into a drawer for my granddaughter's to play in when they come to visit- sometimes they go into a flat rate box for me to send on to someone else when it's full. there's always a use for them regardless of size- decide what works for you & pass on the rest- there's always someone somewhere wishing for scraps in all different sizes.

For me, a scrap is anything small enough to throw away. Larger than that is put back in stash. So I guess my 'scrap bin' is the waste basket.

I confess I never kept my "scraps". But now that my studio is organized and I have places for storing scrap fabrics I am saving any fabric that is 3 inches or larger.

Anything and everything depending on how I feel. One day I may hate a certain piece of fabric - into scraps it goes. The next day I might find it just perfect for a certain PP block and that day it*s my favorite piece of cloth.

I save very small pieces for applique, especially if it already has fusible on the back, and I also have some much larger pieces that I consider scrap because there isn't enough to figure into a quilt unless it would be a doll quilt or something like that.

Maybe lint?!! Bear, you are so funny!:D

A scrap for me is any size I "might" consider using. Some days I don't really like the fabric so a piece 3x4" would go into the trash. Other days I'd keep a piece 1" x 2" for a scrappy log cabin.

Yep, a scrap is "mood dependent". :)

since i know people who happily accept boxes of pretty small peices of fabric i really don't throw any fabric in the trash- i keep a flat rate box under my cutting table & any piece of fabric i don't want to keep i toss into that box- when it's full i tape it up & send it to someone who will use them- there are always people looking for scraps for something-even if it's for stuffing dog beds- the only thing that goes in my trash is threads- frayed edges with nothing of substance left-

I save down to 2" for myself. anything smaller goes into a box for a friend that had the patience to to work with tiny pieces. many pieces I send her end up in a cathedral window quilt she is hand-sewing. The rest she uses for the intricate dolls she makes.
Batting i save to use in purses etc.
Selvedges, trimmings etc. go into the trash. might seem wasteful to some, but I only have so much space. i know what i will actually use and what just takes up valuable space.