>>2951944
you're not missing anything, your wife is dumb and a fear monger. there will be no pressure if you turn the water off first, and even if you do fuck it up, it's going to cost the same to have a "pro" look at it whether or not you tried to change it first, so why not try?

just make sure you replace it with a brass valve and not a plastic one, use teflon tape, and thread it in by hand until you can't anymore, and then doing one or two more turns with a wrench. if it's an old heater, you're going to want a big wrench to take off the old valve. you're going to need to drain the whole water heater before you change it out (obviously). don't be worried if you have a bunch of calcium and mineral build up come out when you drain it, that's normal. if it's a slow drain, wiggle a screw driver in the hole to knock stuff loose. it would also be smart to change the anode rod while you're doing this. then it's going to take a couple hours before you have hot water again after turning everything back on