I'm subleasing to a tenant and they left behind tons of stuff so I'm using it.
How do you use their things?
I steal their stuff to use at night.
You really should not use people's things without their permission. Think about how you would feel if you found out that people were stealing stuff from your apartment and using it without asking you first. You also could get in legal trouble if they report you to the police.
So what if they report me to the police.
You will go to jail for theft.