My house is perfectly safe, and the area i live in is relatively peaceful.
I lock the door only at night, during the day i don't feel the need.
However, living in a big town in an area that is overall wealthy, and close to Paris, i avoid going home alone too late at night, and i'm really careful about the things i carry with me. I also avoid taking certain lines of public transport. I also avoid the train stations in general, and certain underground stations with a high tourist rate. It's common sense to me, when i go out with friends we stay somewhere until the first trains in the morning, rather than separate our ways in the middle of the night.
I also have a map in my bag, so that i always have a backup solution should i feel unconfident.