Currently Being ModeratedMay 15, 2012 6:00 PM (in response to Dwightmc)
As you have already discovered, the only event repeat intervals available in the iOS Calendar App are:
Every 2 Weeks
If you are using iCal, you will have to adjust your desired custom repeat interval using the iCal application. Any computer capable of using the iCloud Web App calendar can also be used to adjust a custom repeat on iCloud.com.Mac OS X (10.7.4), iPad 3G, iPhone 4, 20GB iPod Color, iPod shuffle
Currently Being ModeratedNov 29, 2012 7:06 PM (in response to Dwightmc)
There are only limited manual options for repeat on iOS calendar if you enter your appointment manually. A workaround is to use Siri. Siri can set appointment repeats any way you desire (every other day, every three days, every three weeks, every 5 months, etc)
Currently Being ModeratedApr 10, 2013 8:52 PM (in response to Alex0530)
I'm sorry, but that's really stupid. I just got an iPhone4 (so no Siri), and I find custom repeats to be one of the most useful tools iCal has to offer. I'm glad I can still set them up from iCal on my macbook pro, but it's really unnaceptable that such an essential feature is left out of the iPone version.