How much protein you need depends on a lot of things, but the 2 biggest factors are caloric balance and level of carb intake. The harder you're dieting and/or restricting carbs, the more protein you need in order to prevent muscle protein breakdown. 1g protein per pound of target bodyweight is a good middle-of-the-road benchmark to work from. Rarely is more than 1.5g ever needed, unless you're chronically undercarbed.
An even better starting point, if you have a record of it, is historical protein intake. If you're aware of how much protein has been affecting your LBM status under your given exercise conditions, then it's a simple matter of adjusting up or down from that point depending on your goal. Be aware that most BBers (recreational & competitive) easily take in more protein than they need.