When do schedules change?
 

Does anyone know how often Delta changes their flight schedules (either timing or equipment)? Or is there a typical time of the month when future flights are modified?

Got a reservation booked in April and am wondering when the best time is to go online and see if everything is still looking good.

Most will tell you it depends on so many factors, that there isn't a general "rule" for all flights..unfortunately.

typically schedule changes are loaded en mass every other to every 3rd weekend. (It is almost always over the weekend)

Schedule changes are almost always on Saturdays; otherwise, I know of no pattern.

Delta will run a schedule change of some sort almost every weekend. Major schedule changes are much less frequent. Usually start sometime late Friday and will run through Saturday, depending upon how major the schedule load is. If it is a major schedule load, they sometimes have to lock up the seat maps until they have time to sort through who had what (although we all know that is not always a major concern for Delta). "Generally", once you get to within 60 days of flight time, the schedules do not change significantly, but that isn't a guarantee.