I sometimes take my cue from the road.
If I see a lot of "double doubles" on tags, or "triples in the Pick 4" on tags, it generally indicates that we will see such a combination in the Carolinas.
Today I saw a few double doubles, 9911-1188, etc. But who knows.
There are only 100 "double doubles"--minus the ten that become quads--so maybe only 90, but these are such illusive creatures. I know which ones are supposed to show from the calendar cause I put together a list of about 8 of them that will show over and over in 2013. These were extracted directly from the yearly calendar collection so no hard work there if you are playing all-states.
Lately I've been having some success in identifying combinations that "trigger" double doubles, but they don't always do it, so consistency is a problem. Sometimes these combinations will trigger a "triple in the Pick 4" and sometimes a "double double". My theory is that if the trigger has a "non-resistent" digit in the combination, that a double double is likely, but if the fourth digit is "resistent", it will trigger a "triple in the Pick 4". So more testing is needed.
Still I find double doubles to be fascinating combinations so I know they have to have triggers, but they show so infrequently, I wonder if it's worth trying to find a trigger rather than just playing those that have already shown themselves on the yearly calendar.
Things that make you go "ummm?"