I have 8 pairs of shorts.

I find after less distance than that the lycra can start to get a tad see-through.

Four of those I do not wear when I will be with other riders, or I wear with a short pair of yoga pants over the top. However, when they get this thin, the padding is also getting thin...

Chamois (real chamois) seems to have a longer paddability life than non-chamois...

I don't treat shorts any different from other clothing... warm or cold wash (depending on what I am washing, and hang outside in the sun inside out whenever possible to dry...