We wash Boo's scalp once a week. Period. Regardless of what style she's wearing. A healthy scalp is so important to healthy hair. And besides, we don't want her doing the "weave pat." Yarn extensions are no exception. Yes, washing hair with a style in does make the style get fuzzier, and in the case of yarn extensions, the yarn will probably slip a bit, but it's a small price to pay to keep Boo's head healthy.