I'm testing Ubuntu development version and I want to know when to update the packages. The last time I update the packages regularly, the system broke and I had to reinstall the OS.
I think that the first answer is missing the point. The question is not when should I upgrade to a development release but "What is the best time to update the current development version of Ubuntu? And the answer to that question is - Daily.
Some of those who test the development release update it two or three times a day. Some issues are caused by some libraries being upgraded and other related libraries not being upgraded. And so an application or daemon closes unexpectedly. This cannot be reported as a bug because it is due to obsolete packages.
There are two ways to solve this.
1) Run Synaptic Package Manager, locate the obsolete package and mark it for upgrade and then click apply. You will be shown what packages are going to be upgraded, installed and removed. Make sure that Ubuntu-desktop is not going to be removed. I have found that Synaptic sometimes tries to do that. Find Ubuntu-Desktop and remove the check mark.
2) Wait a few hours and run Update manager and you may see that the obsolete packages are about to be upgraded. Sometimes you might have to wait a couple of days.
A recent update removed Ubuntu Software Centre and it could not be re-installed because a certain package was not ready. Two days later an update brought in that package and I was able to re-install Software Centre.
A lot of issues with the development release are solved by doing daily updates. I have found that changes to the development release are done in small steps and so an update dated development release is always the best state to be in.
Always, when using a development release, be ready to do a re-install of Ubuntu. Sometimes, it is the quick and painless method of getting back into the action. although finding out how to fix breakages can also be interesting.
Early this morning I ran an update and when I booted just now I found that the application lens was blank. This problem was solved by re-installing the application lens.
Part of running a development release is having problems and fixing them. Daily updates are the best way of keeping the OS fixed.
First of all, I would say that if it's more than a small inconvenience to you if the system breaks utterly, then you probably shouldn't use it in the first place. Though it's highly valuable when people do and file bugs when things go awry. Though the goal is for it to be usable throughout the development cycle, with the massive amounts of changes, there's always a chance that something breaks.
Milestone releases (Alphas, Betas and Release Candidates) are usually fairly safe points to upgrade. But every release is different, and the situation changes during development. The Precise cycle (intended to become 12.04LTS) is a fairly conservative cycle and things have been rather stable, though there have been issues and breakages. The cycles leading up to 11.04 and 11.10 was much more turbulent.
For these reasons, it's difficult and somewhat dangerous to give general advise about when to upgrade, except for the milestones. Whenever you upgrade a development version, you should first read and understand the changes. You might want to join #Ubuntu+1 on the Freenode IRC network. This is where testers hangout during the development and you can ask others what their experiences are.
This will become less of an issue in future versions since – thanks to BtrFS – you'll be able to just undo the upgrade or even boot into a previous version of the OS. So, if an upgrade totals your system, you'll just boot into the state before you upgraded, and no harm will have been done. You can actually do that now. Ubuntu has BtrFS support, at least in the Alternate installer. Using it properly, however, requires a little bit of reading. (Ubuntu is a little bit special in that area) But if you intend to do a lot of testing, and follow the development cycles, I'd say it's probably worth it.