I am lucky that this is quite an easy one for me.
In the 1970s, while train travel was still the default way of travelling in Europe, I read quite a bit about the environment and decided never again to fly.
Because of the relative costs, I have probably had fewer holidays abroad than friends in a similar income bracket; maybe once every few years rather than a few times a year, and mainly to France.
For the holiday of a lifetime, after my husband and I retired, we travelled by freighter and train to America.
Once we travelled by train to Poland, once by train and ferry to Morocco and on another occasion to Istanbul. For the holiday of a lifetime, after my husband and I retired, we travelled by freighter and train to America, where we also covered thousands of miles by train.
I emphasise that this is over the course of a lifetime. But we have no regrets and the most amazing memories.