I've hit some snags in the last two upgrades (which I've been able to resolve with time, patience and AskUbuntu :) so come 12.04 I'm considering a side-by-side installation. Perhaps even installing a pre-release before that (because virtual machine testing can't reveal hardware-related issues).

So, let's say I installed a side-by-side version. As far as I can tell this splits my existing partition and installs a brand new Ubuntu on partition 2. If all goes well, there are no hardware issues, and my favorite apps seem to be working, how do I switch to a one-sided installation? If I can't, how do I do a side-by-side installation the next time?

(And, am I crazy to consider using a pre-release version to do a side-by-side installation?)