As Joe mentioned, getting to 0 states is best but not required.
As for your primary question, I do not think that there is a documented limit to the # of states. The biggest issue that I have seen when the states gets into really large #'s is related to performance. The number of queries being performed on the data is causing the RDBMS server to be slower than expected. Also remember that performance can be impacted in many different ways with versioned data (old indexes, statistics, lots of data in the delta tables, etc.) and is the biggest driver of good Enterprise Geodatabase maintenance.
When it comes to maintenance scheduling, I say start with every other week (depending on the amount of edits) and increase / decrease from there. Many people start with and stay on a weekly cadence.
--- George T.