Was it the extra cash, or was it your options having been greatly reduced on account of your age?

At what age would that be then, when you are over 60 but can still be employed illegally, or over say 30 when the students find you too old to relate to? When can you expect to earn less on account of your age? It wouldn't surprise me if schools want to hire 21 year old teachers as opposed to 31 year old/or old enough to be their dads for the the juniors. I suppose a professor like Turnoi is exempt from this age consideration and can get a uni job in Beijing aged 92 and in a wheelchair like Hawkins.