18yo and out of HS means move out, pay rent, or be the live in servant.

"In a few years...."

Nope.

He turns 18 and graduates HS, whichever is the later.... and he has self support requirements.

Refusing to pay rent?  Re-key the locks and put his crap on the curb. He can pick it up before trash day or it goes to the dump.

For this type of kid a burning platform is necessary to get them to launch/jump towards self supporting adulthood. Light that platform, add fuel as necessary, and scorch his tail feathers until he leaps from the nest.

My Skid (SS-31) had options.  Apply for, get accepted and get the full meal deal mom and dad college package anywhere in the world he wanted to go. We were on him to graduate on time and get his applications in.  The more frustrated his mom and I got with him, the more withdrawn he became.  He finally sat us down and told us that he knew completing a bachelor's degree was important but that he was not ready to put in the focus and effort to be successful. So, it would be a waste of his time and our money for him to attend college/University.   14 years later, I am very proud that he was self aware and confident enough in our relationship to realize  and communicate that.  Though his mom and I were ready to string him up by his toenails back then. He drove us nucking futs for a bit more than a year.

Upon communication of that epiphany we gave him a choice. He could stay living at home if he was af ull time student, or worked full time, or be a part time student and work part time. Or he could either leave and figure it out for himself.

He was not motivated to get a job.  His plan was to be a sofa rodeo rider.

Nope.

We turned him into our live in beck and call chore boy.  His mom went CPA on him with an ever growing daily chore schedule.  It was at least 8hrs of work a day.  If he got it done by the time his mom and I got home from work, he could cook us all dinner then clean up after dinner then to it all again the next day. If he failed to get it completed, he was on the curb when we left for work the next day until we got home. Then he had to finish what he failed to complete the previous day and what was scheduled for his day on the curb or .. curb.  

He only tested us twice.  Once in the late summer when it was hot.  No food or water other than the garden hose.  He learned what we did as kids regarding garden hose hydration.

He tested us again in the late Fall. It was chilly, he was wrapped in his bed comforter on the back covered patio for that day.  He never tested us again.  4mos as our beck and call chore boy and he enlisted in the USAF on the delayed entry program.  He reported for basic 4mos after that.  He remained our live in beck and call chore boy for that 4mos as well.

Because he chose to go into the military instead of go to college on our dime, we bought him a new car as a combination HS graduation/Christmas/Enlistment gift. It was the last major help we could give him at that point.

He is approaching his 13th service anniversary in the USAF and intends to serve at least 7 more to qualify for retirement.

I get the Skid's desire to save his money. Good for him. However, spending your  marital money isntead of his own cannot be part of that goal once he is 18 and out of HS.  That trains him to depend on you and daddy instead of being a viable self supporting young adult.  If parents have the resources and are willing to fund University or trade school, great. But, there has to be standards of performance that are firmly enforced even when mom/dad/SPs are capable and willing to provide that support. The same applies for those who want to live at home and not go to school... or work.

IMHO of course.

At 18, when done w/ HS but not in college?

He should be paying for his own vehicle, gas, insurance. He should be paying his own phone, entertainment apps, food. If he were in our home here, he'd be paying a token amount of rent/elect/water and he'd have a move out date. 

My personal opinion is that until a child is 18 and has graduated from high school (unless child drops out or fails due to lack of effort, in which case just 18), the parents should provide food, housing and basic necessities without contribution from the child.  After that, I think there's a large spectrum of acceptable situations.

My parents are wealthy. They paid for college and all living expenses during college for those of my siblings who wished to attend.  None of us was ever charged rent for living with my parents. I moved out at 18, but DH, DD, skids and I moved in with them - rent free - for a few months while we were in between houses a couple years ago (we sold one before closing on another).  We're all still on their phone plan.  They bought each of us our first car (I'm still driving mine).  From an estate planning perspective, this makes sense for my parents. My siblings and I are very fortunate. My DH, OTOH, was pretty much on his own (financially) after HS graduation. He lived at home for a year before joining the Army, but paid his mother rent. He was working and paid for his own car, gas, insurance, phone and personal expenses. Most people I know are in between these situations.  I think what is appropriate depends on the personal circumstances of each family and each child. Steplife complicates it, of course. 

With at !8 yo...either in college, or working full time paying rent.  A good parent will put this money in a college account to be given back when kid seriously go to college.   Not some on line school in N Dakota    But if his living at BM's it's not much you can do except keep him at BM's 

Here is a plan.. tell your SO that his son needs to pay rent.. and after marginal cost of increased utilities is taken out.. have him save the rest for his son... also give him a deadline.. 2 years.. 3.. whatever you and he can agree on.  How does he intend to earn his living?

The problem with not enforcing rent is his son will be tempted to spend more.. take it out of his hands.. dad can even say he will be returning a portion of it at the end.. but his son will be too comfortable otherwise.

If he's not paying rent then that savings needs to be paid to you/your husband to hold/invest for him. 
 

Its way too easy to blow through savings when you have no bills and using said savings to pay for cushy lifestyle then be looking crazy n broke at the end of the living situation with no savings who turns into a permanent live in freeloader

If I were you I'd get him used to paying household expenses by charging him a small portion of rent, utilities, etc. 

You need to ask daddy how he invisions his son as an adult and have him describe it in vivid detail.  Then ask him how SS will get there with no plan? No push ?  Some kids need to be pushed. My oldest was like this.   The need to feel the pain and suffering of not being coddled and expectations put on them.  Either or stuff.  

This little freeloader needs a short sharp reality check.

Yes he should be paying towards household expenses.... he's working, earning money. You say he wants to save up for his own place? Sounds as if he wants you and your husband to subsidise that, by living with you rent free till he's ready to purchase his own home..

In the meantime, you and your H (and you say you're not wealthy) need to be thinking of your own future - retirement etc. You can bet your bottom dollar SS won't subsidise you two when you're old!