I’m certainly not fessing up to a date, but the first Euro trip I did was on a near new early 750 Kawasaki two stroke...and it did the gearbox crank seal on the way home from the SoF and I put 5l of oil in the gearbox...
Since then averaged anything between 2 and 5 trips a year ever since until bloody Covid, things to concentrate on....have a plan if you break down, and what riding gear you are going in A. For when it’s pissing down and B. For riding in the heat.
Only ever put up with one other rider travelling with us, and he still reminds me of the rules I quoted to him...When we are 500 miles down the road and your arse is killing you and your either freezing cold or absolutely cooked....I’m not listening...and he stuck to those rules for many years, the free WSB/Moto GP tickets I used to get did help 😀