If you are using Node.js, particularly on Heroku which mandates a specific version, and need to work across multiple versions doing this manually can be frustrating (and insane). “No such module” problems like this and this have naturally led to some nice tools for managing NPM and Node.js versions.
I have found n, like it’s name, to be simple and useful and haven’t yet had any issues with it.
What is your tool of choice? Do you use one or just do it manually?