I think 2-3 times a year is plenty. I would say 3 is ideal. Most guys train 6 weeks before each fight, so thats 4 1/2 months of training right there. That leaves you with about 2 months or so in between fights to spend time with family and what not, and let their body recover. They most definetley deserve the time off between fights, what they put their body through training and in the ring is crazy.