Imagine you had a daily income of 40$ each day in bitcoin, what would do with them and where would you invest them ?
I think that with the $40 daily you should invest in the project safe low profits of about 1% per day. E.g. https://ethtrade.org/agent485529
Where would I invest if I had 40$/day ? I will invest money in learning knowledge first, because when we have knowledge, we will earn money successful, if not we just can go fast but not far.
With 40$/day you will earn enough money to invest in yourself in about one or two months, but what than? I think OP meant something else when he asked this question.