To determine how many protein shakes you need, you should first determine how much protein your body actually can use. You need adequate protein to enhance muscle growth; excess protein is not better.
Most exercise scientists agree that one gram of protein per pound of body weight is a very generous protein allowance for athletes building muscle mass. (More likely, 0.5 to 0.75 grams of protein per pound will do the job if you are eating plenty of calories–but let’s be generous.) This means a novice 180-pound body builder gets more than enough protein with 180 grams of protein per day. He can easily consume that much with one quart of skim milk, two cans of tuna (i.e., two sandwiches at lunch) and one large (eight-ounce) chicken breast at dinner. Consuming protein shakes on top of this simply adds (expensive) calories. You could more wisely get the calories from carbs to fuel your workouts.
There are numerous approaches to determine your daily protein requirements and the results for most adults range from as low as 70 grams of complete protein per day to as high as 200 grams per day depending on your lean body mass and your activity level. If you take in to much protein which is highly unlikely it will store up in your liver and kidneys so i would not take more then 200 per day. find out how much protein is in one shake and drink up to 200 per day. and only take that much if you are trying to gain muscle.
There second most important thing you need to know is the amount of protein your body needs as it may vary from one person to other. A general rule defined by most of the nutritionists is 1 to 1.5 grams of protein for every lb of your body mass. So you must calculate it according to your weight.
Once you have calculated how much protein your body needs in a day than you should know what percentage is coming from your daily normal routine diet. For example if your body require 260 grams a day and the food you eat contains 180 grams of protein than you know that you need about 80 grams more therefore you can take them three times a day. One shake at mid morning, one at lunch and the last one just after the workout.