An alternative, less cynical viewpoint, would be that it actually does cost more to host couchsurfers as you get older. You get more stuff. You get better stuff. You get more attached to your stuff. All of these things make it more costly to host couchsurfers since the expected cost of broken stuff increases proportionally to all three of those things. It’s one thing to host a couchsurfer when all your furniture is Ikea and all your dishes are plastic. It’s quite another thing when you’ve picked up a proper sectional, a nice coffee table and proper plates and silverware.
An alternative, less cynical viewpoint, would be that it actually does cost more to host couchsurfers as you get older. You get more stuff. You get better stuff. You get more attached to your stuff. All of these things make it more costly to host couchsurfers since the expected cost of broken stuff increases proportionally to all three of those things. It’s one thing to host a couchsurfer when all your furniture is Ikea and all your dishes are plastic. It’s quite another thing when you’ve picked up a proper sectional, a nice coffee table and proper plates and silverware.