Do you pre-wash?
Do you purchase and stack in your fabric storage area only to be removed for cutting then sewing?
Do you wash then starch?
Do you treat different fabrics differently based on the use (or stashing) you have in mind for it?
For the record I once washed and now I soak (using hot-ish water with no liquids or soaps so no need to rinse) except I don't do this for pre-cuts. But I do do it for batting.
I line dry and then iron and store.
I feel a little guilty about all the water - but that is one of the reasons I now go down the soaking route.
Why do I go to all this trouble? I want to remove as much of the manufacturing chemicals as possible. I want to test for colourfastness (and sometimes am extremely glad I did) . I want to preshrink - the crinkly look is not for me. It shocks me how grey the soaking water comes out after a soak (or how yellow for the batting). I don't know if it is normal chemicals or it is dust accumulated over the manufacturing, shipping and sitting on shelf . I do know I don't want it stitched into my sewing.
The reason I don't go and add the starch back in is that I don't like the idea of adding back in a chemical after I have just gone to all the trouble and time of removing them. And if I iron it and cut carefully I can still get accurate pieces.
This is not the only way to to treat (or pre-treat) your fabric but it is the way I use right now.
What do you do? Why?