Thanks for the comment though, pretty much as I'd suspected.
Another note: if the frequency is too high in any one period of time, I suspect there's burnout. Political advertising seems to hit this point -- a friend in a heavily campaigned state a few years back used to respond to candidate spots with "F--- you <name>" when yet another of the multiple-times-an-hour ads would sound.
You need repetitions, but also spacing.
There's also ... I forget the name, but "Pass the Biscuits, Pappy", a 1930s / 1940s Texas politician. Ended up governor, before getting caught up in a corruption scandal. Early name recognition came from his fame as a bluegrass / popular music performer.
Its different for each industry though, some do 90% of spend for the holidays.
If you're interested in some advertising theory, give Media Planning: A Practical Guide by Jim Surmanek[0] a shot. It's short and pretty accessible.
[0] - http://amzn.to/1Q7mGVe