It's the gear that you don't even think about that is sometimes the most important. Ever since I signed my first contract with a mobile carrier I have HATED mobile carriers. This all changed the day that Google announce Project Fi (now Google Fi).
I actually switched from my iPhone 6 to a Nexus 5X just so I could use Project Fi. I ended up missing iOS too much and eventually got back in with Virgin Mobile, which at the time, seemed like the least evil option for an iPhone carrier.
I started reading about people having success getting Fi to work with iPhones provided you activated the SIM on an android device first. After coming back from a trip to France where I dropped $60 for 10 days of local data coverage, I was ready to give it a try. Aside from voicemail acting weird (who calls anymore anyways?), everything seemed to work great! There were limitations of course; without the proper hooks into the OS that the Fi app enjoyed on android, network-switching and wifi-calls didn't work. I could make a call though and even more importantly, data worked fine.
Much to my surprise, just a couple months after I had been using my iPhone on the Fi network, Google officially opened up the service to iPhones! The app and service are still a bit limited compared to what you would get using an android device on the service, but it's a step in the right direction vs. using an unsupported device. The service works great and I love knowing that wherever I land, pretty much anywhere in the world, I'll turn on my phone and be greeted with an active data connection at no extra charge.
This takes out so much hassle and additional expense than having to buy and activate a new SIM card for wherever you find yourself. You can leave the hotel with your camera and phone and be confident that you know where you're going and what to expect thanks to a reliable connection. It makes the world feel a little bit smaller and you more at home in that world.
If you feel like trying out Google Fi, use my link and after 30 days we'll both get $20 off our bill (or don't, it's up to you, but do give them a try!!).