If you are going to be the only maintainer of your stack, in a single machine, and you are not going to pause your work for a few months, you don't need Docker.

If you are going to be the only maintainer of your stack, in a single machine, and you are not going to pause your work for a few months, you don't need Docker. If you are planning to bring more developers, or there is a risk that you will have to leave the project for long enough to get some form of dependency rot, then Docker will eventually make your life much easier. Though Docker or any other container technology requires a non-trivial time investment.