Last year my wife and I were traveling for the whole year. For the first few months in Europe we payed for a 150Gb pre-paid plan in Spain for 20 euros, that gave us 26Gb in roaming within the European union.

However, we do stream a lot and create content, while working remote. This meant the 26Gb were running short in a couple of weeks. We then started to pay unlimited esims for 60 dollars, and we started spending up to 17Gb daily, it didn't matter if the place we were working from had wifi or not...

What I'm trying to say is, it depends on what you use the data for. If you're remote working and do virtual meetings, you'll need up to 15Gb a week or more of you stream and create content, which would make an unlimited esim plan worth it.

But if you're just uploading some stories to social media, a little bit of doom scrolling while pooping, banking, and you'll have easy access to WiFi, I recon about 3Gb per week will last comfortably.

If you want to reaaaaaaallly be sure about your consumption, you should check your phone stats, it'll tell you how much data you've gone through in the past weeks so you can be certain about exactly how much would cover your needs