I didn’t expect it to be cheap, but still, my laundry bill on a recent hotel stay in Singapore came as a sticker shock. I had to pony up more than $80 for a few T-shirts, some socks and some boxers — cash I could’ve spent on, say, five Negronis, a spa treatment or almost a week’s worth of laksa, satay and chicken rice lunches at the city’s excellent food courts. It was a moment of weakness (and a hectic schedule) that had me reach for the hotel’s laundry bag, but the bill served as a sobering...