While I'm not exactly sure when you think its good to spend bitcoin, I disagree with this. Bitcoins were made to be spent, not held. The ability to spend them is what gives them their value. When you spend your bitcoin, you are fulfilling its purpose, its destiny. If everybody held their BTC, well first of all there'd be no market, and second of all it would be no different than a Ponzi scheme.

The tough thing about using bitcoin as a currency is when you buy it at a higher price and then it goes down significantly... This has always been a risk, however. Thankfully BTC has spent more of its life going up than down.