Copper pipe running to a washing machine washing connection. No shut off valve on that line, so if you want to replace the washing machine you need to shut off the water to the whole house. Irritating

I want to cut the pipe and add in a sharkbite shut off valve. Obviously I need to make 2 cuts and remove some length of the pipe. Shockingly, Google has gotten so bad now it can't even find me this answer.

How much pipe do you cut out? 1/2 inch? 1 inch? More?

Doing lots of plumbing work on my recently bought first house. I've used sharkbites in easily accessible areas like under sinks and whatnot.

But now I'm moving on to a bigger issue. I have one long run of hot and cold in the crawlspace that's old galvanized steel line that I want replaced. The water that initially comes out of that particular line is brown, and in cutting a part of it out, it's indeed really disgusting on the inside and significantly restricting the flow. Oh and the galvanized is just welded straight to the copper on one end🙄.

I want to replace the galvanized with PEX, but I have no experience with welding or sweating pipes together. The sharkbites from copper to PEX seems very easy, a little to easy. I want it to last as long as the PEX does, and it will be in an extremely inconvenient area in my crawlspace to keep an eye on it.

Are sharkbites good long term if used properly? I recently got some quotes for a smaller portion of this line where the plumber was going to use sharkbites and pex, but I'd just like some other thoughts.

Edit/update: thanks for all the replies and some solid discussion!

Just FYI, after reading all the comments and watching some YouTube videos. I think I'm going to practice sweating some copper>Pex fittings to copper pipe (I actually have most of what's needed for soldering already). If I can get confidant with that I'll go with that option. Otherwise sharkbite to replace where my two galvanized lines come out of the existing copper line, I'll insulate those sharkbites as well since it will be under the house (and of course attach it right).

Also helpful was the PEX discussion. Going to go with PEX B for new lines as I'd like to keep the tools around for future use and don't want to spend the $500+ on a Pex A tool. Probably oversize the PEX B line as any fittings for B reduce the size and flow and my run will be fairly long. Also, maybe I'm overthinking it, but I read PEX A may have a slightly higher chance of leaking some chemicals into the line (according to some California standards).