While I am not into racing or even fast riding, every once in a while I end up being faster on Brompton than people on road bikes in sporty clothes.

While this may seem minor, if life makes you ride in a variety not particular familiar places, invest time in the manner in which you might want to mount phone on the handlebars, including in the rain, as the latter can surprise you away from your lodging that you do not know how to get back to. Also collect a variety of navigating apps. Google Maps may work fine for bike at home, but not in places you may get to. When the internet barely works at a hotel, downloading a 200MB map may turn into a nightmarish challenge. I keep 12GB of maps for the whole world on my phone, so I can pretty much recover no matter what.

I log only 10 days/month away from home. Having a bike along for riding makes a world of difference for a variety of reasons and training for me is not even on horizon