10 BTC is good amount to hold if the value reaches to $10k but we are not sure what would be price of bitcoin in future so playing safe I believe 30 BTC can be a good amount to hold even if the value doesn't reaches to $10k mark, so if the value is around $5k then 30 BTC can take care of us during retirement.
I agree with you the only problem is how easily can you get 30 coins. 10 is still hard to get but more achievable.. for now because it won't last long and I'm sure cheap coins will be over.
Bitcoin's value if ever reaches to the dream value of Satoshi, then these 10 BTC would obviously be making this guy live a king-sized life after retirement...
It's just that however much someone tries to save, they should do so, and even trade during panic sells, but with caution...
They should not just save, but grow their coins if they want a secured future with BTC alone...