My son (17) has a debit card, but leaves it at home and uses Google Pay on his phone instead, even when travelling away from home in the UK for a few days to visit friends etc. I'm concerned he will get stranded if he either
(a) loses his phone or
(b) runs out of battery.
His counter-argument for scenario (a) is that he will be more likely to lose his card if it is in a separate wallet because he uses it so infrequently. Plus, he wants to travel light, not have multiple things to carry.
He doesn't really have a counter-argument for (b), other than "it has never happened".
We live in London, so he does carry a 16+ Oyster Zip photocard in his phone case. There isn't space for his debit card too, so he probably just needs a better case. I know my niece has a card wallet stuck to the back of her phone, but it looks to me like it could easily come unstuck.
Any recommendations for a good secure setup for a phone and a couple of cards? What does your equivalent young person do?