One good trick is to only install the "security updates", like if it says it's an urgent security bugfix, install it. A lot of linux software updates, you won't even notice any difference if you install the new version or stick with the old one.
What I do is open a root window, and run "apt-get update". Then I do "apt-get upgrade", and it makes a list of software it thinks it will install. Then I say "NO" and don't let it install all that stuff because I don't care. If the list is small and I am not doing anything important with the computer at the time, and I have recent backups, then maybe I say "yes" and let it do the upgrade.
Instead of a big upgrade, I think for example, hmm, I would like that new version of firefox and the new emacs, so I would run: "apt-get install firefox emacs". That makes it much smaller and shorter to just install the software you want. I bet you can figure out a way to do a similar thing using Update Manager.