How often do you wash your scrubs?

My wife is a doctor. She got upset at me for washing her scrubs, reason being: "I only wore them once". She says they aren't dirty and it will ruin the fabric. I told her that they are unclean and that they should be washed after every wear, especially after 12 hour ICU shift. She also sits on the sofa after work without changing into home clothes... Opinions?