That's a really interesting take on the positive aspects of OCD and one that's not often discussed. Thanks for sharing. :)
You've independently discovered a key diagnostic factor in OCD. :) What distinguishes OCD from, say, obsessive-compulsive personality disorder, is that the sufferer of plain ol' obsessive compulsive disorder knows full well the absurdity of their condition. She understands that doing 12 jumping jacks before leaving the house won't stop it from burning down, but the overwhelming "why not be safe?" urge compels her to do it just in case.
It's unfortunate that it seems to take a toll on your private life. This past year I have developed a habit of double checking the front door even though I remember bolting it.
It's an interesting thing to ponder whether some mental disorders are extreme versions of adaptive behaviours that we all do from time to time.
What's worse is that while I've also always been a chronic key checker, last month I still managed to lose the keys. On top of that I didn't even lock myself out - either they're somewhere in the apartment(I'm at a loss here because I went as far as going through the trash - to no avail) or the single time my OCD didn't make me check if whether I left them in the lock I did just that and somebody took them.
What really helped me get out the door in the morning, and still does, is actually to video myself doing it. When I got a Palm Zire 72, for the first time I could actually leave within a normal interval because I had a continuous, raw, time stamped record of everything I did from checking everything was off and secure to leaving the apartment and driving away. I refused to ditch the Zire until the iPhone 3GS because the 2G and 3G only did stills. To this day I still do it with my Pixel when I'm flying solo.
Which brings me to the other thing that helped: my very patient wife, who reminds me she saw me do it, you did it right, and get your butt in the car, darling.
The damnable thing about OCD is that a little is very valuable in my regular line of work (medicine). Without it I wouldn't be as careful, I don't think. It means it won't let me take shortcuts and it forces me to be thorough, and that's a very good thing in that business.