Lessons learned and tips #2

If you can, prune/remove all services/libraries you don't really need. Fewer things to update, and fewer security bugs to worry about.
Running the latest Fedora Core or Ubuntu from 6 months ago is often much more trouble than it's worth.
Full updates of servers every 3 years is not actually unreasonable, so Debian stable (plus testing cherrypicks) or RHEL are the way to go for servers.
Depending on your server setup, partial upgrades may be better for you. If so, choose a distribution that allows this (like Debian).
If it is possible for you to do so, the best way to do a huge update is incrementally a few packages at a time (this is still mostly possible with Debian where you can cherry-pick updates).

If you can, prune/remove all services/libraries you don't really need. Fewer things to update, and fewer security bugs to worry about.