if I have stable bitcoin income, let says 0.5 per day, I quit my day job and give full time on bitcoin, but as of now saving bitcoin is my first priority then learning for some bitcoin investment to get my goal in the future.
I think that is too much to ask for a daily income, and you cannot make it working for bitcoins to be realistic, you will only have a chance to make that if you are rich already to have a capital for trading or short term investment.
I don't know if there is a job that can give you 0.5 btc a day that is possible for a semi monthly income but for a day that is impossible.
Unless you have a business or you are very good trader with a lot of capital and coins to trade.