Normally I never did, even in big cities and dangerous neighbourhoods I’d leave the keys on the door, or leave it half-open to get air in the summer etc. I figure if someone really wants to break in, they’ll find a way, and your average amateur won’t dare come in if he sees there’s someone there. I lock when I leave of course, because I don’t want someone figuring out the place is empty and sneaking in while I’m away.
In my current home the door doesn’t even lock properly, and normally you could just push it and come in. All my friends knew that trick and I’d told them they could come in and wait for me if we were supposed to meet and I was late. Or too lazy to go downstairs to open. Now that lock is completely broken anyway, and it won’t close properly.
This was how I always was. But ever since last year and a series of events I’ve become paranoid. Not only do I bolt the door now (as I said, it won’t lock, but there’s a pair of heavy bolts on the inside that make it impossible to open without the use of explosives), but I also booby-trap the place when I’m away for more than a day, and double-lock from the outside.
And yes, all this (the first phase) does reflect on my personality. It took 6 burglaries (plus 1 in my car and 1 at my workplace though) and an attempt against my life for me to change my life-long habit. I was finally persuaded that perhaps people are not all that nice after all.