It doesn't have to be a big baroque thing. When there's a dotfile I configure regularly, I move it to a Git repo and use stow to put it "back" into place with a symlink. On new machines, it isn't long before I try something that doesn't work or see the default shell prompt and go "oh yeah, I want my dotfiles", check out the repo, run a script that initializes a few things (some stuff is machine-specific so the script makes files for that stuff with helpful comments for me to remember the differences between login shells or whatever) and then I'm off to the races.