Obviously this depends on where you are located. Such as if you live in an expensive place in the US or Canada, then its a lot more than in other countries. Also if you are young, middle age or older.
This is obviously true. I lived in a province wherein I can buy food with a cheap amount compare to the city. But the reality is we are having an inflation. The amount if $10 today cannot buy the same thing $10 can buy five(5) years or ten(10) years after. My needs also changes especially if I already have my own family to raise. I know bitcoin price rises like how my expenses rises but considering that Bitcoin price also goes down and nobody can actually tell when it will pump or how fast it can rise I cannot be so sure. Due to that I know I cannot directly answer how much bitcoin is exactly I need to secure my future. Expect the unexpected better to keep on earning bitcoin than sorry because you make yourself believe that 10 bitcoin (assume) can already secure your future.