How long do the effects of Thermage usually last? How do you schedule the re-treatment cycle?

I am considering Thermage treatment, and my biggest question is how long the effects last. Since it is an expensive lifting procedure, I am curious about actual experiences regarding how long the effects last after a single treatment and how often repeat treatments are recommended.

For those who have received Thermage, when were you most satisfied after the procedure? I would also like to know for how many months you felt the effects of improved skin elasticity or fine lines, and whether you felt the effects gradually diminished over time.

I hear that people usually get treatments once a year, and that longer intervals are acceptable depending on your skin condition. I am curious to know how those who have actually maintained consistent care for several years determined their treatment schedule.