Can it be difficult to find a seizures' trigger?

Sometimes it's difficult to identify triggers or define them. We know commonly that sleep deprivation can lead to seizure, but seizure may not be happening each time they are sleep deprived. Now, the threshold at which these trigger could cause seizure can be variable, so that's why it's difficult to identify them. But once they are identified, if patient have seen a pattern that when they are sleep deprived each time they have been having seizure, then avoiding those situation can be very helpful for them to avoid seizure.