Always a difficult call, from experience and as a result of many discussions with retired couples etc., whilst you may have more time to be flexible about when you travel/holiday when you are retired, as you get older usually diminishing health can restrict your ability to travel in the same way you could in your 30s/40's.
I've been very fortunately working in roles with companies that have allowed me to travel the world at their expense from my very early 20's for many many years. However, I've slowed down my own international travel in recent years, as I tend to enjoy my own bed more. I found the best years for travelling was in my 40's/50's, when I had more disposable income and still an appetite to travel vast distances by air. There are no guarantees in life and sometimes you have to take the opportunity no matter what initial sacrifice may cost you.
Wise words John re not waiting to retire before taking on a road trip or two.
My good lady and I did our three European trips in the Mog when in our fifties, and again I was almost 70 when we again headed South to take in the LM Classic and head down as far as Beynac, though on this trip we enjoyed the comfort of air con and auto box in my good ladies 4x4, which is just as well as our capabilities in the heat of France and daily mileage covered with ease were found to be somewhat reduced from previous trips.