I usually develop in VM's where the machines are very well defined so it's easier to build a build machine. In the end though this usually means that the absolu

I usually develop in VM's where the machines are very well defined so it's easier to build a build machine. In the end though this usually means that the absolute package requirements are held by the project repo so what needs to be installed is based on that. So if I need to start a project or rebuild a system to do a project I can generally use the project itself as guidance on what to install. After two or three builds I have usually cleared all the dependency hurtles. The only thing that really breaks down is not having your dotfiles available, but for me those are backed up/in SCM. If you are familiar with building projects from scratch it becomes a lot easier to understand dependencies and grow the system to what it needs to be, and with VMs it is that much easier to start with a blank slate that you are capable of blowing away and not even trouble secondary workflows.