iPhone use when WiFi is not available

It also depends on if your smart phone is unlocked or can be. Can’t use a eSIM unless it’s unlocked. Some plans won’t unlock your phone until it’s totally paid for (AT&T, I’m looking at you). That’s my issue right now, so I just had to factor in the cost of my international plan on my recent trip to Paris. I also preferred using my own plan, so that I could keep my own phone number and didn’t have to depend on public and mostly unsecured WiFi.

depends on how long you are traveling, and how many days you plan to use your phone without wifi access. There are many options for esim cards, so easy to use, but you do loose your home number. You could probably cover your entire stay for $10-20 using an esim card. $10 a day gets pricey if you just use the phone for a few minutes during a day to check email or find something using maps. Just get an esim card - it's so simple. We use Airalo...

I have been using Nomad eSim for my international travels. I have an unlocked iPhone and my local US mobile plan is awful for international travel. Price depend on location but you can get regional esim (Europe/Asia for example) or country specific. My recent trip to Morocco it cost me $20 for 10GB of data that was valid for 30 days. I was only traveling for 10 days and didn't use all that data even though I was using my esim data a lot as free wifi was difficult to get. It even worked in the Sahara desert and on the road. You can get cheaper plans with less data on it.

I setup the eSIM for data and enable voice over wifi. I still got a call from my work IT department to my cell phone when I was in Norway (they didnt know I was traveling) about a security issue they were sharing with all staff.

But I have also set up a free Google Voice number and before I travel, I forward calls from my local number to google voice. That way I get a transcript sent to my Gmail of any voicemail.

How important is it to keep your phone number so family can contact you?
My husband is not computer/cell phone literate and a geezer who doesn’t like change. Adding an overseas phone number from a sim/esim will only confuse him. Neither of us need that grief. It’s easier for me to use Verizon’s monthly international plan so he can call me if needed. I also have Google Voice set up so I have the option to call our landline via WiFi.

Which use cases?

Transferring social media messages can wait for next WiFi .

For navigation you can use apps which so not need connection. e. g. Sygic GPS Navigation.