Avoid needing to drive if possible. In much of Europe we can get around very easily using trains. We did need a car in Ireland when we went out to Dingle, but so far that's the only time we've used on in Europe. I don't even like to drive around Disney, when we've driven there we generally park the car the whole time we're onsite.
Limit luggage to one 24" suitcase and a smaller carryon (backpack or duffel, not a 20" suitcase) per person. Anything more gets very unwieldy on trains. Easy on a 1 week trip, not as easy on a 2 week trip.
I don't cook or do laundry on vacation.
We stay in hotels, not AirBNBs or anything like that. I don't trust them.