If you are a frequent flyer, then consider getting one of the best international SIM cards on the market. Use it as your default for calling, messaging, and surfing overseas. This should beat your roaming services hands down.
It will not be as cheap as getting a local SIM but it could be a hassle changing these every time you’re in another country. One travel SIM will allow you to communicate everywhere so there is less stress.
Compare the rates of various brands. Some might offer cheaper calls while others dangle cheaper data. It’s up to you to decide which ones are more important in your life.
Consider their extras as well. Most will provide one phone number while others may give out two for different regions. Some might be bundled with an app with nice perks and free services.