I have, and got burned the first time. First, check prices at several kiosks. You'll probably get wildly different prices. Second, make sure you're getting a genuine Apple OEM battery. The first time I was sold an aftermarket 'AA' battery, and about 6 weeks later the voltage dropped and took out the motherboard. It's worth paying a bit more for the real thing. Finally, while they have your phone and are working on it, stay close and watch. It's not unheard of for less reputable kiosks to swap out other parts if they get the chance. I went to Greenhills in Manila, if that makes any difference. Good luck!

I'd only go to Apple, not even authorized repair centers. Breaking the screen while changing the battery is really common, and the battery life is shorter too.

Yeah. It went well until he broke my screen while taking it apart. On the plus side, he replaced the screen at his own expense. On the minus side, it was a total piece of poop and the touch was all janky. Long story short, I now have a new phone, and my least favorite in-law has my old one.

If you're in Manila, go to Greenhills. They'll sort you out.

If I need a battery replaced on an iPhone from the US, would that be a problem at Apple?

Yeah. My new 18 Pro Max is on order, and right now I'm typing on my 15 Pro Max, which is in great shape except for the battery. Before I sell or give away this 15 Pro Max 1TB, I figure I should replace the battery, which is down to just 65% capacity.