While I can understand the thermostat and pissing in a gallon container, why can't you still feed your compost pile and cut the grass with whatever you want?

but you can still do things that are not as radical. You have to give up some things, but there is still the simple things---buying foods in season, thrift stores, not buying things you don't need, etc. When you are living with someone else, there is always a give and take. I am sure that if I lived with another person, they would have to stop doing some of the things that I do...but I would not give up everything. But don't give up your soul.

BTW, I use a cheap paper shredder to shred newspaper for the compost pile. It saved a lot of time. And I have been told that all I would have to do is just tear it up a little (and I even have a friend who just puts it in rolled up and it decomposes) and it would work fine, but the shredder works great. Plus it saves a lot of time if you are cutting it up by hand.

Let's face it, even if you weren't there, she'd be using most or even all of the energy and water by herself. So instead of heating one residence all winter at 70 or so and a second at 55, you're only heating one at 70ish. (At a guess)

If you were elsewhere, two lawns would be mowed instead of one (unless you were in an apartment).

Etc.

People crowding together reduces resource use, although as you note, it could be reduced even more if everyone in the crowd could be persuaded to go more frugal.

As far as water goes, maybe you could offset with more efficient appliances? We switched from an older washer when it was getting wonky to a newer one with something called 'precise fill', and our water bills dropped by about 15-20% a month instantly.

The utility bills here didn't go down much when I left and they didn't go up when I returned so me being here instead of at another place is in itself frugal living.

But I gather that's not an option. I like Bloodaxe's take on it. Kinda like car pooling in a Cadillac, which is better than driving a Cadillac and a Prius.

and winterizing the big house during that time. We did that earlier this year when propane went up to $6 a gallon. At that price, I figured it would have cost us about $1200 to heat the big house just for one month. The largest gas bill at the small house was $85.00 something and that was for heat, hot water and cooking.