Just started playing apartments - after years NOT. And found some interesting things.. and some irritants.
Roommates are not like regular controllable Sims: I can direct them to do something, but not to STOP! If I see they need neat points I can direct them to clean..OK. But if I direct them to study from a book THEY DON'T STOP! Their needs seem to decay much slower than regular playables. And they spend most of the time gone "doing chores" --what's with that?
---Is there a mod to make them more controllable?

The main, controllable, person in the apartment can try to make friends, become lovers - not sure they CAN. But they can't ask the roommate to move in (cause they already live there- duh) so guess they can't get married.

Odd thing: I directed the roommate to potty-train a toddler; toddler was almost ready to pee itself, but this ONE & ONLY potty training made it potty trained.

And if a playable in one apartment falls in love with a playable in another apartment, can one ask the other to move in?

I believe the same cheat codes that makes pets controllable work on roommates. It's been a long time since I played with them. Last I knew, you could move them in and marry them, but it was glitchy?

I could try that mod, but yea still would be glitchy.? Can't move in?

Yes, the cheats that work for pets also work for roommates. I have these in my userstartup.cheat file:
boolProp controlPets true
boolProp petActionCancel true

I believe the second one will allow you to cancel actions that roommates are doing. I don't typically control dormies, but roommates I do try to control as they have a TON of free time and tend to get into some drama. I find it helps if the apartment or the lot has some things for roommates to do. I also find it best not to get too attached to roommates as, while they are always around and controllable through cheats, you won't be able to help them progress in their career--they won't be able to get a promotion. I can't recall if roommates can earn aspiration points, either. I think, iirc, they fulfill their wants and fears, but don't gain any points and their aspiration meters don't fill like regular playables. So, after awhile, I tend to get board with roommates and kind of wish they were a normal playable. So I tend to see roommates as temporary, much like apartments themselves--great for the short term, but not really something you want permanently.


Moving in and out of apartments tends to be a bit glitchy, in that the correct amount of money never seems to be applied--you either end up with not enough and the value of your household and the apartment the sims were in is lost, or you end up with way too much money because you sold all the furniture in your apartment. But there are mods. (Like Kestrellyn's Apartment Moveout Finance Fixer.) Best practice in this scenario though is to move out the sim you want to move and then add them to the household via the neighborhood screen, because otherwise you'll probably lose all the money from the household of the sim moving. Usually when I move in sims from an apartment to either another apartment or a regular residential lot, it's like the game doesn't recognize their lot worth and they just come with whatever cash on hand, which is usually nothing. So move out and in via neighborhood screen is best.

I think you can move in roommates with no problem (i.e., as in ask a roommate to join the current household). But it's possible I have a mod in. If you don't see the option, then yeah, you'd have to kick them out and then ask them to move in.

And now for some mod recommendations, now that you're having fun playing in apartments:
Squinge's Multiple Roommates, in case you want more than one, but make sure to pick up Midgethetree's Multiple Roommates Pay Rent and Kick Out Multiple Roommates if you do.
Nopke's Memories About Roommates Fix
Simler90's Apartment Mods
Marhis No Apartment Noises (you might think this one is too cheaty, but if you play apartments long enough, you realize just how annoying the noise is and how unrealistic it is to always make sure your sims' bedrooms don't share a wall with another unit, just so that they can sleep.)
And Kestrellyn's Less attractive vending machines because if you have vending machines on the lot, all the uncontrollable sims are inevitably drawn to them.

Toddlers can be potty trained in one session if their bladder is very low and they have had smart milk.