I am 74 and DW is a child - let me just saw we were born in the same small town hospital in the same room (only one delivery / surgery room) one year apart - her 13 months after me. But I did NOT tell you her age!
We have had the same discussion a few times. What would we do if we did not have the 5er. But we are both in fairly good health and active and the driving does not bother me - but we do not push a lot of miles a day.
We will keep the 5er as long as possible and be faced with the same decision.
Know sooooo many people that have given up rv'ing and soooooo much regret it.
We have had very small travel trailers up to 38' 5er and back down to this.
Cannot imagine anything but a trailer though for flexibility of having the tow vehicle.