To be honest, the question is not the most accurate one. It should be understood that the price of bitcoin changes quite often. For this reason, it is quite difficult to say for sure.
But since its been asked then make use of the current value of Bitcoin at the moment which i do consider that most of the time it would really be sufficient for someone on securing themselves from 5-10 bitcoins but
this would actually vary on where someone do live because we know that there are first worlds to third world which means that monetary value condition will always vary.
Asking out on how much btc we do need? The more the better and there would be no accurate numbers on here.
