When I was in my twenties, living alone, I completely lost the habit of locking my room. After that, he moved in with his wife and had to lock it up.
In the end, I couldn't regain the habit of locking, but instead I introduced CANDY HOUSE's smart lock "SESAME (Sesame) mini" with an auto-lock function in 2018.
It can be attached by simply sticking this device to the key of the entrance, and if it is linked with a smartphone, it can be locked / unlocked with a single tap of the application. In addition, it has an "auto-lock" function that automatically locks a few seconds after unlocking. After installing this machine, I never forgot to lock the key (prior to the introduction, the rate of forgetting to lock was high).
In December 2020, a new model "SESAME 3" was released for the smart lock that smartly locks/unlocks and eradicates one of the causes of marital quarrels in our home. The price is 6,380 yen, which is quite reasonable compared to similar products from other manufacturers.