We had a young woman move in with us as an adult. She was very sweet, but only did the things she WANTED to, WHEN she wanted to. Her counselor suggested this system.
We charged her "rent"-$350. (It equaled what she would pay for an apartment).
We then made a list of things that we wanted her to do so she could "earn it off":
Weekly Cleaning done by 12pm Saturday (the work was agreed upon)$20 (warning:be prepared to do it for them if they don't get it done)
Make bed/tidy room 5 mins./say prayers-$2 a day (her problem if it wasn't done. We included this to help with good habits. Showering/teeth brushing, clean clothes could be added for your situation)
Counseling-$10 a visit
Attending College-$50 a month
Babysitting-$5 an hour
It all added up to rent for the month if she did everything.
She was 100% responsible for her own laundry and bedroom. (I would put the laundry in a seperate basket if it were in with our stuff, and put it out of my way if it was in the wash when I needed the facilities.)
What ever she didn't "earn off" she would have to pay us cash by the end of the month, or recieve 30 days notice. She always "earned it off", but she would beg to babysit at the end of most months to make up for not doing other things throughout the month. That was not so bad for us, though.
We tried to include things that we felt would be not only good for us, but good for her too. Please understand that your family's situation may require different things. You and your husband (not just you) need to decide what is most important for your son and your family and the appropriate consequence.
In our situation, she was told that she didn't have to sign it, but she would then have 30 days notice to move. She agreed to it (begrudgingly), but this worked for us for over 1 1/2 years. She was a joy to have in our home. She enjoyed being treated like an adult. I NEVER nagged. She was responsible to keep an account (check list), or rely on MY memory of whether something got done. (She wanted credit for it so she kept a pretty good accounting).
This was a contractual agreement. So I was able to pull it out if she started in with any excuses or "unfair" attitudes.
We did include that we would provide love, food and shelter. And that we were doing this because we loved her.
I agree with one of the previous posters who said to make consequences for his inaction. You could use this system (without the moving out part) as a mock "real life" system, but instead of giving 30 days notice, you could take away privilages, require babysitting or other chores (of course, to be completed BEFORE he goes somewhere, eats, etc) to free up your time to do his.
Another idea might be that instead of rent you could charge him for meals, car use, rides, etc that he has to "earn" credits for.
He is pretty much an adult and you ought to treat him like one. No nagging. Just consequences. Look up "Love and Logic". I'm sure it can help.
A.