Frequent Locations didn't record a location I have Frequent Locations turned on and it does a great job recording everywhere I go and for how long. A few nights ago I was at a residential address for about an hour, however Frequent Locations did not record it. Is there a reason why?
If you don’t go to a certain location at the same time on a regular basis, your iPhone will obviously not be able to detect a pattern in your various locations. 

It means that you must go to a place around the same time, on the same days, for a certain amount of time for your iPhone to establish a pattern.