This is what I do, haha, constantly. I wish I can only hold my bitcoins never selling them, but life is life. Just yesterday I sold $40 worth of BTC to buy The Official SAT Study Guide and a couple of other similar books.
What I've discovered is that it is much easier to sell bitcoins than any other valuable item when you are in desperate need of money.
Anything that has a public market where people can post if they are buying or if they are selling that item allows you to get rid of the item pretty quickly. You simply dumped your coins. That means you sold your bitcoins to someone that has a buy order. But since the transactions are almost instant here, it's one of the quickest assets to sell. Even other assets or even stocks from a company can be sold pretty quick especially if there's a buy order or if you're selling it for quite a low price.
As a matter of fact, you can even use bitcoin (just like other assets) as a way to pay that thing you desperately need money for. It can serve as a money right away.