Slight Corrections:
1] In all counties in FL or only some? All
2] For buying a handgun? Always
3] For buying a rifle? In Some Counties
4] For buying a handgun or rifle from an individual who is selling their own personal guns at a gun show? In Some Counties
5] From a licensed dealer? Always for Handguns. In Some Counties for Rifles.
In 1998, the Sheeple passed an amendment to our state constitution allowing counties to adopt waiting periods of up to 5 days on all sales of guns where the "public has a right to access." I.E. Gun Shows, Gun Shops, etc...
Only a handfull of counties (Broward, Dade, and Palm Beach are the only ones I'm aware of) have adopted a waiting period on Longguns or a 5-day Waiting period. If you have a CCW, you are exempt from all waiting periods [state and county]. Same if you are trading in a handgun, I believe.