On the groceries - you mean perishables, right, so you don't end up throwing any thing out? Or is there some peculiar alchemy that means money is conserved if you run out of, say, flour before buying a new bag? We've got a lot better over the years at using stuff before it goes off - that was a lesson of career break #1.

Hosting couchsurfers in the hope that they might subsidise our household expenses would indeed be a bit weird :-) We have been toying with the idea of renting a room out again, though. (It'd have to be to a fairly tolerant person, though, given the ubiquity of the kids.)