Development tools and practices for Pythonistas

[CM]

> A lone developer using such a VCS reaps the benefits of this by getting
> good merging support.

While we're on the topic, when should a lone developer bother to start
using
a VCS?  At what point in the complexity of a project (say a hobby
project, but
a somewhat seriousish one, around ~5-9k LOC) is the added complexity
of
bringing a VCS into it worth it?

I've been making changes to code and saving changes to the same
files,
but backing up on Dropbox, which keeps 30 days of previous saves.
I've rarely had to resort to undoing code by calling up a previous
save.
I test each new change as it is made to see if it breaks anything
(not
automatic testing, though), and I don't collaborate with anyone else
as
yet.

Should I bother to try a VCS?