Thanks for your input Nico. Actually, that's pretty much what I've been doing, and what I believe mostly everyone is doing : only updating in case I need to use new features.
It's always good to have someone else point of view though.
For what is worth, Gemnasium just emailed me about a new feature where they seemingly have a CLI that auto-updates deps in your projects granted that your tests pass after the update... May be another approach