I've just come back from a lovely holiday cruising on the River Duoro in northern Portugal. We were a very good group of 17 plus our hardworking TM, Kristina, and the weather was lovely (25-29 degrees!). There was one problem, however, during the week - two of the group had health problems which necessitated them both going to the area hospital at the same time. One had fallen and hurt her wrist so there was a suspicion that she might have broken it and the other had a heart scare. Kristina brought them back later that evening, which is when they told us their stories.
One had a check-up, her wrist xrayed and was given a supporting bandage as it turned out not to be broken but badly sprained; the other had a wide range of tests and saw a cardiologist, leaving with the reassurance that the problem wasn't quite as severe as everyone had thought and with some medication and preventative advice. The difference between the two patients was that one had an up-to-date EHIC, the other hadn't bothered to renew hers because with Brexit she apparently didn't think it was worth it. Result: the sprained wrist cost its owner about 200 euros to cover her hospital visit and bandage while the heart patient only had to pay a few euros for the medication, all her tests being covered by her EHIC.
The moral of this story is therefore: if you are going on holiday in Europe, please make sure you have an up-to-date EHIC and take it with you (besides the one who didn't have one at all, another in the group had one but had left it at home - fortunately, although not in good health, he didn't need medical attention). Yes, it may cost you (it is free to obtain or renew if you use the official site) but that is insignificant when compared with what the medical fees without one can be and will save a lot of stress for everyone involved.
Ann