I do not follow a strict update cycle as I look at the fixes and updates and determine if they address any issues that I am having or may potentially have. For the new features, I look at what those offer also to see if they will help me or my customers. If your environment is stable, secure and functional, why patch at every release?
If I see that the new release has some feature/fix I need, then I will start working on my upgrade plan. I do like to look at this forum to see if people are having issues in the first couple weeks, so this site is a great place to see what is going on. I then upgrade my test environment and let that burn for a while to see if there are any issues.
I would say that it takes me about a month to start upgrading production from the release of the patch. I have not had a situation yet where a patch addressed an issue that was critical enough for me to rush any faster.
I am currently on 9.5.6 and there are a couple items in the 9.5.11 release that are of interest, but I have also heard 10.x is coming soon enough and there is part of me that wants to wait so that I do not need to do two upgrades in a year.