I try to maintain "current" when I can.
My home PC is running an old broken version of Mepis. Lots of things won't install, requiring more current libs, which in turn refuse to install due to conflicts.
So, my work PC is a relatively new Kubuntu install, 1 version back, when means upgrades should go pretty seemless (I hoped, I was wrong). That way I maintain a greater likelyhood of installing new stuff.
That's OK.
I'm waiting on a couple of LCD screens. When they show up, I'll juggle out the video card and install fresh.
It takes me under 30 minutes to put my desktop in working order (at work), since almost all I use is remote access to other systems.