I make sure never to be working with anything less than 5.8 because good Unicode support is so crucial.

On my own box, I track the latest stable release closely; currently I have 5.8.6. On machines I deploy to, I don't care a whole lot about the number behind the second dot. Any version of 5.8 means all the utility modules I rely on heavily are available in core and all the language features I require are around (even 5.6 would be sufficient in that regard).

But I'm a Perl developer, so the Perl interpreter is my core competence and tool of trade. It should be expected that I'd track versions closely.

If I were a sysadmin responsible for keeping 50 variously sized applications available without interruptions on 30 servers, I'd obviously be taking a different view.

Makeshifts last the longest.