Very Seldom and even when i see updates available i will not take them until they have been out for days or weeks. The only thing that has broken my phone forcing a restore is Cydia updates.
Usually, if you don't check for updates frequently, it takes a long time to load the new updates and such. Since I'm checking several times a day, it takes me about 10 seconds to load
I only check Cydia every few days or so unless something's posted here about an update or cool new tweak. As long as my phone is stable, I don't like to update it--that goes for the regular app store as well.
I dont really check for updates, I go into changes maybe like once or twice a week to see what new apps are out there. If there happens to be an update thats an added bonus.... but I never go in with the intention of checking for updates.