I've got mostly 5.10 (system perl) and 5.14 (windows) going, but I've also got an old win98 laptop that's running 5.8, maybe 5.6.

For the laptop I needed a version that worked under 98 and was tiny enough to fit on the drive. I've since gotten a netbook, so it hasn't been booted in a while.

For the 5.10 system perl, I just don't have the motivation to install a side version of newest perl. Its already got //= ops, and I'm not using the newer features.