I tend to be more conservative in OS upgrades in general, so you can take this for what it is worth.
In general once a site is up and running I would upgrade under the following circumstances. This will generally be once a year or less.
1-Response to a technical issue - a problem occurs at the site with a known fix in a newer version and the issue is impactful enough to schedule the upgrade. Or if a feature in use at the site appears in the "resolved issues" section of a Junos release notes and may cause problems at a site.
2-Need for features - as new versions release I look at the new feature section. If there are features that would improve the site I would investigate the upgrade. I will generally wait for the version to hit the JTAC recommended list as well, unless the feature upgrade is very compelling.
3- End of support - the running version for the site goes end of support. To prevent issues with portential trouble tickets I would schedule the upgrade to the current JTAC recommended release
New release Review
When new versions of Junos are released I review the release notes.
A-Are there issues in the resolved issues section that involve configuration parameters we use that should be addressed.
B-are there known issues in the section that would cause a problem if we used this release.
C-are there new features that would be of value
Steve Puluka BSEET - Juniper Ambassador IP Architect - DQE Communications Pittsburgh, PA (Metro Ethernet & ISP) http://puluka.com/home
Thank you all for your responses! I am aware that I am behind the JTAC recommended release but now I have a better feel for how urgent these updates are.
I am in an education environment and would love to contain my upgrades as much as possible. I was hoping to run them either just over summer break or, if needed, over winter break as well which based on spulukas answer seems like it would suffice.