Suppose I enter into a long futures contract to buy 1 ounce of gold at 1200$/ounce for delivery in May 2015. Between now and May 2015, the market price for a similar contract will certainly vary.
Do I need to worry about these fluctuations? Since I have already locked in a price of 1200$/oz, should I care if the market price goes up to 2000$/oz?
I ask because there is this concept of mark-to-market, where a contract's value is recomputed every day, but what does this mean for me when I have already locked in the price? Whatever happens I need to pay 1200$, so do I have to worry about repeatedly marking the contract to market price?