I use a time lock safe to keep self locked. Helps with temptations. I purchased this a couple of years ago and use it all the time.
The safe was made in Germany (Germans make the coolest stuff!) and it's a little hard to follow the instructions, but I finally got it set and rewrote the instructions so I can understand it a lot better.
You can program up to 10 different times for it to open... for instance you can set it to only allow you to open the safe from 11pm to midnight Monday through Friday, or all days... or even just 1 day per week. I set mine to only open Wednesdays from 11 at night to midnight. A little strict, but it works for me.
There is a backup key unlock in case the batteries go dead, but it hasn't failed on me yet. I keep the keys in my car under the spare tire so it would be inconvenient for me to casually go get.
I hope someone doesn't break into my place and take it thinking I keep valuables in it... lol. They would be bummed and I'd be left without keys!