I'm not sure if I'm the only complacent person when it comes to getting a new phone. I usually just put my existing SIM in the new phone and put the new one in a drawer somewhere. I found them yesterday and since I've been having a few issues with my device decided to use the last one I received 2 years ago. Easy to make the change online and it switched immediately. I registered my Wi-Fi calling and have been making texts and calls with no problems.
Lesson for me is the newest SIM is usually the one that works best. 😉