I told him that was silly, that I could gladly change linens and tidy up and make sure people got keys, rather than let his valuable apartment sit empty all summer. So he took me up on it, opened the place up for reservations for most of the rest of the summer, and gave me $50 per guest.
Last weekend, I had to do a full load of laundry with sheets and towels after the five-day stay, but luckily I had a day before the next person was coming. Today's swap meant I had to visit in the few hours between one departure and the next arrival, but I was able to do so... and Ed let me know that the beer in the fridge, left by a previous guest, was all mine. Four beers, four of us in the office today... that could hardly be a coincidence, could it?