I am so used to garment making that I still pre-wash everything that can bleed color or shrink. Since cotton falls into both categories, I do wash it first.

So far I have never had a negative experience from washing to discourage me from continuing. I don't find it extremely time consuming, I don't buy so much fabric at one time that it would take longer than throwing a load into the washer, not sure how it could be that time consuming? I even wash it with clothes or towels, it doesn't get pampered.

I don't like the smell and feel of unwashed fabric either. For the many hours of handling involved in making a quilt, my personal preference is to handle it washed.