I was told when you buy fabric you should alway prewash to allow for shrinkage in the material and to wash any excess dyes out of the material.
Let me know if I am right or wrong.

Don't have pets and no smokers here, so the washing is up to the receiver !

What do you mean "proof" your question?

I never wash quilt material. BUT, I always purchase good quality from a LQS. It makes a difference is you get your material at a craft store or a store that also carries furniture... If I am spending my time and energy to make a quilt I want good material that will last, even if in years it sells in a garage sale!
I was told by two different teachers, one that said is wasn't necessary to pre wash and another that said it was. If the material is good quality it doesn't matter. I also like the softness of a post washed quilt.

That I didn't catch my mistake -- I put "want" instead of "wash" when I typed my question.

I am collecting info about what quilters suggestions are about laundry of already completed gift quilts

I send mine to the cleaners, comes out like brand new, no puckering. Very pleased with them.

Some teachers said that the chemicals were hard on the fabrics. Generally I tell recepients to wash in cool water and do not over dry.

Since my cats like to "help" when I hand quilt I like to wash after finishing a quilt for a gift. I also like to see how they come out after a gentle wash and machine dry. It also fluffs out the batting inside and gives them a more "comfy" look and feel. I also preshrink all of my fabric as soon as I purchase it to prevent surprises as to bleeding or uneven shrinkage after a quilt is done.

I love the wrinkly look I get when I wash the quilts. And to remove the starch or basting spray.