User blog comment:RansomTime/An introduction to Pywikipediabot/@comment-1393830-20120722181854/@comment-3508190-20120722184510

I found this on Bot_policy:

Edit throttle and peak hours
Bots running without a bot flag should edit at intervals of over 1 minute. Once they have been authorised and appropriately flagged, they should operate at an absolute minimum interval of 5 seconds (12 edits per minute). Bots should try to avoid running during the busiest hours, as they rapidly use server resources that should be reserved for human readers and editors. During these hours, they should operate at intervals of 20 seconds (3 edits per minute) to conserve resources.