What "work" is should be defined, or rather it stopped making sense. If it is just the process - something like placing banners, looking at Google analytics or writing emails or chat, then I barely work 20 hours/1200 minutes a week netto (it used to be much more before). Maybe it is no more than 10 hours if I have to count seconds (72000).
But if it is also thinking about work and being online in standby mode, then it is 168 hours a week and forever it will be (even on my 2 months "vacation" now).
There is no upper age limit but people over 60 years old are not recommended to trade bitcoin in consideration of price volatility and risk tolerance.