We were diving there in September and we were told one year. I was curious too as we hadn't dove in 7 months. (A dive Roatan vacation in February) One guy we met had not dove in 1.5 years and he didn't have to do a refresher. Maybe because he had his AOW and had about 150 dives in his log book. Who knows. They said there are alot of people who only go there once a year and they are okay.
Couples Negril - September 2011, 2012, 2013 and have just booked 2014
Scuba Club Cozumel - Jan, Apr & Nov 2012 and Jan & Nov 2013
Cobalt Coast, Grand Cayman - May 2013
Retiring & moving to Cozumel, Mexico in early 2014