I always wear jeans/slacks twice, unless its something unusual like you've been walking around a festival all day long. For normal days, when you're typically in an air conditioned office or home most of the time, there's very little perspiration from your legs. I just leave a comb in the back pocket to remind me I've already worn that pair once.
Similarly, sometimes I'll have been working in the yard all day. Those clothes will go right in the washer, but then we'll want to go to a friend's or whatever for an hour or so before coming back home and changing into PJs. If I've only worn a shirt for a short period I'll rewear it again too before washing.
This saves a lot of ways:
- There's less wear and tear on the clothes from frequent washing
- You use less laundry detergent
- You use less electricity, gas and water since you run the washer and dryer less frequently
- And since the washer and dryer are run less frequently they last longer.