At Cidell's suggestion I am turning this into a blog post, you seasoned bloggers seem to think of everything in terms of 'how can I format this for my blog?' (which seems to me, 'do I have a picture relevant enough to justify my blabbing about it?'). So here it is, hopefully someone will find this useful.
I hate drycleaning. I wash everything, including silks, bras, wool sweaters, lined skirts, etc. I do however use delicate wash bags, a front-loading washer, and delicate detergents like baby shampoo depending on what I'm washing. About the only thing I won't throw in the wash is a blazer, too much structure to get screwed up there.
One of the big benefits of sewing your own clothes (to me) is the ability to prewash fabric before making a garment. Most fabrics shrink up to some degree when washed; weaving and knitting processes can place a lot of tension on the fibers. When you expose the fabric to water, heat, and/or steam, the fibers relax and assume their final form. As long as you pretreat the fabric in the same manner you plan to clean it when it is done, you can pretty much eliminate any sizing surprises down the road. A few caveats would be some fabrics (like denim) shrink progressively, meaning they shrink a bit more with each wash. I wash new jeans 3-4 times before hemming for that reason. Also, I've heard some silks (like dupioni) lose their sheen when immersed in water, and of course anything with a lot of structure or interfacing (like blazers) don't do well in the washer either.
If you are too afraid to wash your entire yardage, you can cut swatches and test those first to see how they behave. Cidell found these awesome coatings at Michael's fabrics that I immediately ordered some of, they are double-faced cotton with a 'classic' stripe pattern on the reverse. She sent me swatches to test so I washed these 3 in cold water, baby shampoo, delicate cycle, and then air dried.
Other information I obtained from this experiment was the fabric is already somewhat water resistant, it kind of beaded up when I took the swatches out of the washer. The red swatch looked like the color had soaked through to the tan stripe side at first, however once it dried the color returned to normal. Don't ever assume one color will behave exactly like another! And finally it hardly frayed at all, I wouldn't expect a tightly woven double-face to anyways but that's good to know.