I'll chime in since I found myself in this exact situation, renting with a "friend" who turned out to be a huge asshole.
Some things I encountered:
1. All my nice furniture got trashed.
2. Constant mess everywhere all the time.
3. They would stay up all night blaring music, practicing their shredding, drinking, partying, god knows what else.
4. Pretty much the only thing they didn't do was bring girls over, haha.
I moved out early and surprisingly the other 2 roommates stepped up and paid the rent on their own, shocked the hell out of me. However, although I came back and got my stuff out and tried to clean, they left the place TRASHED. Carpet was literally ruined, they left their garbage everywhere. Left all food in the fridge/pantry which I'm sure went bad after the power got cut off. Keys were not returned to the landlord for an additional month after that, it was essentially a nightmare and probably the shittiest point of my life.
However, while we didn't get the security deposit back (yeah, right), we didn't ever hear from the landlord again after his request for the keys. The landlord (3rd party management company) was an asshole in all dealings we had from the very beginning of the lease. I was too embarrassed to go and hand deliver the keys because of my roommates so I just fed exed them to him.
At one point my roommate even called the landlord to complain about mold growing because of a leaking faucet that was partially caused by said faucet, but mostly just because he hadn't cleaned the shower once in 2 years.
Also, the same roommate, who was essentially a hoarder (inclduing beer cans, garbage, food leftovers) ended up getting pretty sick and had to be put on disability for a while, IMO as a direct result of his deplorable living conditions.
Now I'm out of it and haven't spoken to any of them since and am living in a nice clean house.