Data storage and aging

Personal information and email on your iOS device is stored indefinitely, with the following limitations and exceptions:

The storage limit for 
BlackBerry Work
 data (mail, calendar, and contacts) depends on available memory on your device. In controlled test environments, as many as 5,000 emails and 3,000 contacts were successfully synchronized with the user's 
Microsoft Outlook
 account.
In initially synchronizing your Calendar, the timeframe is set to the past three months plus two years into the future. There is no practical limit on the size of your Calendar. However, depending on the device, performance will degrade with a very large set of data.
Email, Contact, and Calendar data is stored in a database, except for the body and attachments to emails, which are stored in an external flat file
Because Contacts data is stored in the database, there is no practical limit on the number of contacts. But, again, very large data sets will tend to degrade performance, especially on older devices.
There is no cache for attachments and therefore no limit on the size of an attachment.
BlackBerry Work
 synchronizes the entire body of emails without limitations on size, although synching and attachment downloads will fail when the device runs out of storage space.

Old data is not purged automatically; you must purge old data manually by permanently deleting it.

If your device ever runs out of space for new contacts, you must delete existing contacts to make room for the new ones. Be sure to do this from the device, not from your desktop business account. To preserve contacts before deleting them from the device, use the Export feature on your desktop or laptop. Note that you must first export the data from your business account and your desktop or laptop before deleting it from your mobile device.