I've spent a lot of time in the past cleaning up the messes of people's
borked Windows systems. By default, Windows PCs always have the OS and user
files in the same partition, so when the OS dies, as it inevitably does, you
have to painstakingly back up all the users files onto a sufficiently large
external drive before you can do a reinstall, or install a new OS.
Learning from this experience, I always advise people to have separate
partitions for / and /home. This means you can easily reinstall your OS, or
switch to a different distro, without having to copy the entire contents of
your primary drive to another drive first and re-partition from scratch
(note: it's wise to do a fresh backup of anything mission critical before
making any such changes to do your drive). I find a 16GB partition for / is
usually enough (anything larger than 30GB is really a waste of space).
On my systems, I always have a second primary partition the same size, which
I use for testing new versions or distros that I'm thinking about using, or
just curious about. At present I have two swap partitions the same size as
RAM, one to go with each primary partition, but from now I will just use one,
for reasons Magic Banana has explained in previous thread on this topic.
