Change default 3 months event series period to multiple longer choices

When the 3 months default event series ends, there is no warning or notification. It just disappears. Very random and many accounts drop off and with 300 accounts there's no way to keep track. We add new accounts continually and the 3-month series ending is unpredictable and not manageable. We should be able to choose from multiple defaults. We should receive notifications when the event series ends so it can be easily extended.