While working on various projects, every developer in the deam can add his libs, extensions and settings, problems arise when those changes are to be applied with other team members, ranging from component x has not been installed to minor tweaks that are important but were overlooked while setting up.
Vagrant, one of the many tools that you may have heard about but did not have a change to try, is used to solve exactly that, to simplify the local dev environment setup, while keeping everything synchronized between team members.