What is the minimum amount of bitcoins a poor person should have? and the minimum time it should be Hold/retained?
Your question cannot be really answered, as everything depends on the country where you live, the amount of money that you can earn, the amount of money you can save, the profits you want to achieve, the moment you buy your coins, the strategy that you decide to use and your specific goals, so as you can see your question is too open-ended to the point it is impossible to give any answer to it unless you were to give us more context about what you mean.