I always keep it locked. Not out of paranoia or anything, but in case I would forget to lock it before I go to sleep or something.
Also, somehow it helps me feel more like I'm in a private place lol.
All the time reguardless of whether anyone is home (i.e. I'm paranoid)
The unlocked when someone is home and locked otherwise (i.e. I'm naive)
Never reguardless of whether anyone is home (i.e. I have nothing worth stealing)
The locked when someone is home and unlocked otherwise (i.e. I live in a prison cell))
I always keep it locked. Not out of paranoia or anything, but in case I would forget to lock it before I go to sleep or something.
Also, somehow it helps me feel more like I'm in a private place lol.