Do you wash fabric before you use it? I have had several people tell me not to. I usually test a small piece if I think it will run, but otherwise I don't wash it before hand.

All the time.

I dont wash my fabrics first, unless I am using reds n whites together, which I only did once.

nope! Sometimes I will rinse and hang dry fabric that I am afraid will bleed light the HUGE ammounts of red and blue that are going next to the even larger amounts of white/cream! lol I like to post-shrink instead of pre-shrink!

I always wash fabric.

I had a horrible experience with a designer's brown fabric. I used it in one of my Dear Jane blocks. I spilled my soda on the block and rushed to run it under COLD water. That fabric started to bleed and never stopped. I threw it into the washer and ran it over & over. Finally threw the 2 yard piece away. Thoroughly disgusted and have never bought that designers fabric again!

i only wash batiks. they are a bleeding mess in many of their colors. or if I think that it will bleed then i will but otherwise i don't.

I don't wash. Nice to know that Batiks bleed. I make several baby quilts and always warn the recipients that the quilts should be washed separately the first few times.

it depends on lots of things...if it's batik's, hand dyes, or any i think may bleed, i pre-wash; if it's flannel, homespuns, or a loose weave fabric, i pre-wash. if i absolutely do not want something to shrink, i pre-wash.
if the fabrics are good- high quality, quilt shop fabrics and i am making a bed quilt i usually do not pre-wash; i wash the completed quilt after binding. which i always do, no matter what, even if the fabrics have been pre=washed i still wash the finished product.

I always wash my fabrics before I use them. Not only for sizing and making sure they won't bleed/fade or whatever, but also to wash away the chemicals used in manufacturing. Also, I think about all the "hands" that touched these fabrics before I bought them, washing them gets rid of any germs or dirt that may have got on it (can you tell I work in health care lol?). Washing them gives me a peace of mind and an easy feeling while working with them.
Just my two cents.

I used to but now I don't, unless they're batiks or flannels, unless I'm making a rag quilt.