Thought this may be helpful for anyone considering sim cards/ phones and travelling without.
Returned from 5 weeks in Europe, including one week in Paris and spent many hours researching sim cards, asking advice on TA and needlessly worrying. In the end I decided not to purchase a sim card but took my phone (Android) for the reassurance of having all my contact phone numbers with me. I used the phone as well as my camera to take photos and found that was an added bonus. Would absolutely do this again.
I also took an Ipad Mini which was great. I didn't take it out of our accommodation and used it with the free WiFi which was available in all the places we stayed. It was great for keeping in contact with home via email and also to book things online. I also used it to take photos inside and from our accommodation.
I saw heaps of people out and about with IPads,using them as cameras but I think that even the compact size of the mini is too cumbersome to be carrying around on a daily basis.
When travelling between places, I had the Mini in my handbag and locked it in the room safe during the day.
Some people on TA queried what I would do if my partner and I were seperated whilst out and were unable to contact each other. We simply always made an arrangement of where we would meet if we got seperated!
There were a few times when we needed to use a phone and we always found staff at the accommodation were more that willing to make the call for us. Our apartment in Paris had a phone which we could use (we used it twice).
I will do the same thing again on our next trip; the only drama is that I now have 3 devices with photos on them!