Where by "live 12 volt wiring", you mean "live 12 volt wiring, , but only 'live' when both the ignition and the brakes are on (or sometimes the tail-lights where they use dual-filament bulbs), which is suitably fused so it wont catch fire if you short it, and which is completely safe to touch unless you manage to pierce through your ribcage with two conductive spikes and connect opposite ends of the low-voltage supply directly onto your heart muscle", right?

Seriously, I'm trying to imagine any scenario where ham-fisted attempts to change a brake light bulb could result in anything more dangerous than a mild surprise and a blown fuse if you manage to short the contacts. You are, in my experience, _much_ more likely to injure yourself kicking the cat 'cause you end up so frustrated having to remove 47 easily breakable plastic clips holding the shitty carpet/trim in the trunk to get to the bulb - than being in any danger from a 12V electrical system, live or not.

And, as someone who lives where out wall outlets provide 220V AC, and who's taken more than his fair share of belts from not only 220V but also 415V three phase power, I find it vaguely amusing when people are deadly afraid of puny 110V electrical systems ;-)

I did not mean the post to be offensive. I apologize.

Ok here is where experience has taught me that your conclusions are wrong.

Similarly, replacing a light bulb on a car is a job the owner can do without the cost of a professional.

A lot of people cant do that. And I mean a lot. Same with wipers, and even windshield fluid. I even had people coming in to check their tire pressure.

Just because you can do something for yourself, does not mean others can do it. I cant, for the life of me, correctly sew on a button. Just cant. I pay people $15 bucks to sew on a 10 cent button. Am I dumb? Probably. But I can sew and they can. So I pay them whatever. Same with cars. I fyou can do it yourself, then more power to you.