This is a little something that I do to save me time, money and sanity. As soon as I take my pants off for the day, I look through all my pants pockets and remove change, papers and chapsticks. Then I button and zip my pants. This way, I know when I put them in the washer if the pockets have been emptied or not. Now, I don't have any more melted chapstick tubes or ruined pieces of paper with important phone numbers on them.
It's also a good time for turning the pants inside out. Blue jeans especially are much less likely to develop holes before their time if washed inside out.