You notice a deprecation warning in the logs, or an email from GitHub and you make a 1 line commit to bump the node version. Easy.
Sure you can make typos that you don’t spot until you’ve pushed and the action doesn’t run, but I quickly learned to stop being lazy and actually think about what I’m writing, and get someone else to do an actual review (not just scroll down and up and give it a LGTM).
My experience is same as the commenter above, it’s relatively set and forget. A few minutes setup work for hours and hours of benefit over years of builds.