Looks like the author only uses one session he calles "work". What I really like about sessions is that it allows for isolated contexts which are easy to switch (prefix-s get prints you a nice list [1]).
Right now I have seven sessions open [1]. Three are work projects (they usually have windows for vim, db console, etc.), two are university courses (vim, matlab), in one session I'm learning some Haskell, and in the last one I'm working on an open source ruby gem. If I had all these windows in one session only, I'd constantly be switching to the wrong windows.
> What I really like about sessions is that it allows for isolated contexts which are easy to switch (prefix-s get prints you a nice list [1]).
I always end up doing the same as the author (out of bad habit), when I should really be using windows more often (to split out dev work, irc, uni work, etc). It's good advice and stops the too-many-windows problem.
Also: what theme are you using in that screenshot?
[1] https://github.com/chriskempson/base16
[2] https://github.com/fphilipe/dotfiles/blob/master/tmux.conf#L...