Well there are various factors. For instance, I have large amount sitting in my wallet. I still use them to purchase from vendors because truth be told - by the time I place an order, usually the next day (and definetly by the time my order arrives), I've got more $$ sitting in my wallet because the BTC price has gone up! So I'm barely dipping into my gains to purchase oftenly, and it still doesn't affect the value of my coins in a signifcant way. I just hope they keep going up for eternity (which won't happen).