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.
I always felt the number had to been minimum 10 if you asked me this years ago. But now with news articles and videos saying btc true value is somewhere in the 300-400k range... well that 10 btc number certainly is a bit high. I guess the number probably is minimum 5? Then again you hear old videos where people say... just make sure you have just 1 bitcoin...as that is enough. Thus if it goes to 1 million dollars... well that is a lot of money. Even after taxes, that is a lot. But when people say its half a million or a million, well then that number could drop to say 2 or even 3.
And i see many people on this forum talk about not having 1 btc and its their goal to get 1 btc. Obviously back then, it was much easier with the low prices. But now... anyone who wants 1 btc need to spend 25k... thats a ton of money for most people and most people don't even have that in their savings. But for someone who is from the West... thus in the US or Canada... what number would you say that should be? Of course it could be in a wealthy country in say Asia, Europe or Australia. But you get my point. I got to assume if you talking about 10 years down the road or more... it has to be minimum 5? Or minimum 10? Or is 10 a bit too high?
Indeed there are so many people who dream of owning one bitcoin now, I'm included and I can't deny the fact that back then it was much easier to own 1 bitcoin unlike now that the price is high.
Anyway back to the question I don't know if owning 5 or 10 bitcoin will be okay for the future, cause I think it totally depends on what price bitcoin will be trading at by then, if the price of bitcoin dips to $10k (which is unlikely to happen) then 5 bitcoin alone isn't enough, but 10 bitcoin could be okay since it will be about $100k maybe you can start up something with 20% of the money, but if bitcoin will be trading above $50k like it is now, then even 5 bitcoin can secure a future for you and your family.