I've got a few pairs that were 3x - 4x that much, and I wash them after every day's ride. Wearing unwashed shorts is a fast track route to developing problems in areas you really don't want problems. If you want your shorts to last then don't throw them in the machine with towels, throw rugs and tennis shoes on the highest agitation and hottest water possible. Wash in cold water on delicate/handwash cycle with a fabric safe detergent like Sigvaris washing solution (or just handwash them in a sink), press them in a towel to remove most of the water after rinsing, and hang them to dry.