We all have busy schedules in my household so invariably everyone has the house to themselves at some point every other day or so. It's nice to have that alone time to decompress, read, nap or masturbate. I think everyone should have some private time. I also often have to work after dinner and sometimes if everyone else has gone up to bed, I'll enjoy some solo time after finishing up my work for the next day. It's also a time for me to cam with other guys here on occasion.
Growing up, I knew my father worked in his basement woodshop on weekends both to make things and to enjoy the magazines he had (not so secretly) stashed away down there. I always respected his time and knew if he was down there, I'd be safe jerking in my room. Now I try to give others the same respect.
A few of my buddies say they always jerk in the shower but that's never been very relaxing for me. Also my wife and I are in and out of the bathroom when the other is showering and though she's well aware that I masturbate, I still feel a bit self conscious being walked in on. I'm also fortunate to have periodic business trips that give me the freedom to fully enjoy the privacy of hotel rooms.
We're soon to be empty nesters which will certainly affect my habits.