A lot depends on the contrast of the fabrics you'll be using. If it is a high contrast I tend to prewash everything. That said, I have a red/white/black quilt in my pile that did not get prewashed. I will simply throw 4 color catchers in the wash when I do wash it.

You can do a color test on your fabrics to see if they will bleed. Either snip a piece of fabric off the edge and put it in soapy hot water or take a wet Q-tip and rub it over the fabric to see if color comes off.

Thanks for all the tips and suggestions. I'm using lavender colors and a little bit of white. The lavenders don't look like they'd run but I guess you never know unless you try washing them so I think I'll do what was suggested and cut a tiny piece of each fabric to test them out.
I am however ironing everything first no matter what I decide about the pre washing.

I don't prewash unless it's a dark batik (blue, red, green, etc.) I don't use a lot of batiks so this normally is not an issue for me. Also, if you prewash, the washing/drying will shrink the fabric a bit. I like the crinkled look of a washed quilt & figure that if I prewash the fabric I won't get as much of a crinkle look that I like.

i wash all of my yardage. but i've become the scrap queen and i have not washed those

I wash and dry all of my fabric - but that is because of the chemicals on the new fabric destroys my fingernails and finger tips. If I buy precuts I wash them in a salad spinner or in a small lingerie bag.

I am a prewasher. Anything I bring into my home gets prewashed before I use it. I went to a big box store a last summer and after watching a customer come into the store heavily perspiring, she then made a bee line to some fabric in the corner where some very soft cotton was stored. She tried indiscreetly to conceal what she was doing but one of the clerks caught her wiping her brow and face and arm pits. She was ushered out of the store and told to never come back. When that happens the clerks/manager has to take the bolt and cut off at least 2 yards of fabric to make sure it doesn't get purchased because of body fluids being transferred to any one else. That woman was perspiring so heavily you could see the soil on the fabric. They cannot sell this. If it falls on the floor that's one thing but body fluids are another. I personally can only stand the smell of the new fabric until I get it home. I wash everything and especially if anything is purchased at thrift stores or estate sales. I use lingerie bags for smaller pieces than yardage.

I somehow think things in stores that sell "new" things get handled as much - or more - as things in thrift shops or at estate sales.

Sometimes "class" has little to do with a person's economic status.

You don't have to cut and wash them to learn if they bleed. In fact, I think it's harder to tell by washing than by doing a simple bleed test.

Take a white cotton kitchen towel, moisten a corner, and dab or rub on the fabric for a minute or so. If the towel turns color, you have a bleeder. If it doesn't, you're fine.

As others have stated, pre-washing is a very personal choice. There are many good arguments on both sides of the issue. Study everyone's reasons and choose based on what's best for you.

* I personally don't prewash unless my color test shows a bleeder. (And even then, I don't "wash" the fabric, I treat it the same way most fabric dyers treat their hand-dyed fabrics. I think multiple washings is a huge waste of time and water, and most modern washing machines don't use enough water in the first place.)

* I like the crinkly look in my quilts, so I prefer they shrink after completion.

* I don't have issues with chemical sensitivities.

I appreciate everyone's opinion on this. I ended up doing a test to see if my material would bleed and it didn't so I've gone ahead and started cutting everything out without washing the fabric first.

The problem isn't always bleeding when there's color transfer. It can also be crocking. Crocking is more likely to occur when you have a larger load (e.g., a full sized bed quilt) than just a piece or two of fabric, but rubbing with a white piece of fabric/cloth while it's both dry & wet will usually give you a decent idea. Hand dyed & batik fabrics are more likely both to bleed & to crock, so it is a good idea to pre-wash your fabrics if you will be working with either of those.

The other thing to consider is if you are using different types of fabrics together, they might shrink at different rates & it can be helpful, therefore, to pre-wash everything to reduce how much each fabric will shrink once the quilt is complete. However, most modern-day commercial quilting cottons are made & dyed/printed in such a way that they shrink very, very little & are unlikely to bleed or crock when washed properly (cold water, slow speed with dye-free detergent in top-loading washer; tumble dried on low heat). It is, of course, the absolute safest option to pre-wash, but I put it in the same category as giving your purse a good disinfecting inside & out every evening. Sure, there's a good argument to do so, but who has the time?!!