Make sure you buy the right kind of breaker. There are different kinds. may need to pull the old one and take it with you to the hardware store.

That’s my only fear. I hate to have power shut off that long.

Pee on it

I had a buddy that would do a hit of A and pee on his electric fence. Not the same as peeing on 120 or 220.

Just photograph it. Take the photo to the store.

Buy Hop a steak dinner , problem fixed

Make sure you have one foot in a bucket of water... Dan

EZ
no reason to shut down power
only touch 1 wire at a time

It can be done hot, but you really have to be focused. I've done it but I would not advise anyone to do it. The real problem is that you are working with the panel cover removed and there are bus bars and the mains exposed. One slip of a screwdriver or your hand and your body could end up at room temperature or in the ER for some bad burns.

Little more to it if you are changing out a GFCI breaker, but not too difficult. I have relatives in the electrical business in Kansas. I was wiring up a greenhouse. Sent them plans for how I thought I could run 220/240 to a breaker box in the greenhouse then split that into 2 branches of 110/120 for electrical outlets and lights. I hadn't done breaker wiring before so I wanted someone that knew what they were doing to look it over. The breaker box and CBs were pretty simple.

100% agree. Just remember, one small wrong placement of your hand and you BECOME the ground. You BECOME the circuit. And that does not usually end well. I've seen what you do to boat motor tell tales...so please be careful and don't blow it.

There are certain levels of being a handyman. Changing a breaker is upper level. It does not take much time, but a mistake is life threatening. Don't do it hot if you have never removed a Deadman cover before.
If this is in the garage and you are sweating, electricity it 10xs more dangerous

You will need to wear arc flash gear.

Why are you replacing it?

Very simple, don't even risk it by keeping panel hot. Tell everyone in the house that electricity is going to be off for a minute, undo wire, pop off circuit breaker, replace and turn back on. Super simple, but don't mess around. I always turn everything off, check with voltmeter it is actually off and then proceed to undo wiring. I have been hit a few times in my life and it never feels good. With that said, I really like electrical work. I've installed a few panels and run new outlets and lights. If I had to pick a trade, would of probably picked electrical. Kind of fun once you get into a routine.