for light travel and walkabouts, i usually use the ona bowery which would normally have my xt-1 with 23mm and x-t10 with 35mm. otherwise, if i need to bring a lot more then i use my billingham hadley pro.
in an ideal scenario, i would like to have the 16mm, 35mm, and 56mm... but life is not ideal so in reality i have the 23mm, 35mm, and 56mm primes which are very practical for my needs.