I've been travelling to Germany, two or three times most years, since the age of 13 - so over forty years now!

Being British, I have no national ID card, and I don't drive so have never had a driving license, so in theory I need to carry my passport with me all the time

I don't

I have never been asked for ID, not even when reporting a stolen mobile 'phone, other than showing my passport on arrival & departure, so I don't know what I would have done if I needed it

I have had the misfortune to be in the situation where my wife left two days early, taking my passport with her, and the Germans could not have been more efficient or helpful (no surprises there) at Duesseldorf, in marked contrast to the UK who left me cooling my heels for over an hour while they went through the same checks that their Teutonic colleagues completed in under fifteen minutes