Don't know about 15 but certainly 30 (0.975^30 = 0.468) see my previous post.
It's a ll short term versus long term. I can take short term variance but I can appreciate someone owning a small business might not.
Keep in mind to that there is no economy for bit-coins... I can not buy my products from my suppliers with bit-coin, I can not pay rent with bit-coin, I can not pay the power company with bit-coin...
So if the dollar goes down or up in value, it is reflected in the economy of the dollar. In 30 years a dollar will buy less tea, but our customers will also make more as a salary. And while I will make more per pound of tea sold, it will also cost me more to buy.
The reason that the volatility in bit-coin is such an issue for a business person is that we have to exchange them out, since there is no economy in bit coins. I would not care if the value of bitcoins dropped by half if my bills where also dropping in half (because I could pay them in bitcoin.)
People cant start thinking in bit-coins, (without doing the conversion in their heads to their local currency with every transaction) until there is an economy.
-David
PS... just an update for people curious, we have had about 5 transactions with bitcoins, it seems to be working well, thanks for inspiring me to start it up again!