Actually the new law says the duration is to be according to the
manufacturer's directions.  For dogs and cats, that's 3 years.  For
ferrets, that's 1 year.  My vet is going to stick with the manufacturer's
recommendations for ferrets; annually.  I believe most vets will do this
because of liability issues.  Newspaper articles tend to hit the
highlights without all the details.  It's better to look for the text
of the actual legislation.
 
<http://election.dos.state.fl.us/laws/05laws/ch_2005-074.pdf>
[Posted in FML issue 5113]