You can divide your salary amount into several parts. One part you will spend on your family one part you will spend on other expenses and one part you will keep in your savings account and another part you will invest in bitcoins. I don't know your salary amount but if you can plan like this it will be good for you. 

Investing in Bitcoin for the Long Term If you ever need money, you will spend that money from your savings account but never sell your Bitcoin investment. Holding this investment for a long period of time and increasing the investment amount every month will at some point see you reaping good returns on your investment.