I originally put a lot of the content in the wiki here - though since the last 3 years I'm still on TMO but rely on the slower 128/256 speeds less. Was buying datapasses as needed but more recently just kept my physical sim on my device and add an esim with https://www.globalesim.app/ whenever on a longer trip.

Tend to use the https://globalesim.app/p/mostpopular - plan at 10GB which lasts a month - or the 5GB at $18 - In many other countries you can get an esim through a local provider at half to a quarter of those rates.

Suffice to say, the TMO Global roaming is great fallback and ready to use function on the start of a trip, just look for other options as well. For voice, I generally just have my TMO line forwarded to Google Voice and noticed less issues with a roaming eSIM for that - so this avoids ANY voice call charges in or out.

When I have a dual SIM, I keep the TMO SIM on Text and Calls (though use Google Voice for calls) and set the esim to data. In some rare cases I will remove the TMO Physical sim and just run with the esim only