I leave all my fans on 24h and had never considered switching them off at night, I don't know of anyone that does this. I think it's better to keep the air moving as much as possible at all times, but I doubt that switching them off for short periods would produce any noticeable negative effects.
As far as I'm aware plants don't need rest the same way mammals do... I'm not well informed on the topic but I'm pretty sure plants grow perfectly well under 24h of light and "wind". The only advantage to switching the fans off would be to save consumption and equipment life. Where I live a 40W room fan costs about 6.50 Euro a month to run 24/7, and need to be replaced after 1-2 years of constant use.