We have had lots of problems with the timing of email notifications, creation of rss feeds and other cron functions. This is due to slow running of the cron job caused by the load heavy jobs such as scheduled backup and statistics.

To overcome this. We removed the less time critical jobs and placed them in separate files, run by separate cron jobs.

It would be much easier to maintain this split if the cron jobs were divided into functions that could be called from other files. Or better still, have the option to divide the cron up via the admin interface.