(Updated Nov 25, 2013)
We've recently moved to a monthly release cadence for Solaris 10 OS patches.
New Solaris 10 OS patches are now available from MOS by the Tuesday closest to 17th of each month.
The updated Solaris 10 OS Recommended Patchset will be available by the next day, Wednesday, assuming there are new patches released which meet its inclusion criteria - that is, patches which address security or other critical issues.
This enables customers to predict patch release dates and schedule maintenance windows.
This is similar to the monthly release cadence for Solaris Repository Updates (SRUs) for Solaris 11.
Please note that the Solaris 10 OS Recommended Patchset may not be updated every month. This is because in some months there may be no new patches meeting the inclusion criteria. That is, patches which address security, availability, data corruption, or other critical issues.