You should only drink protien shakes if its the only way to keep up your protien intake. You should take on protien constantly throuout the week if your looking to gain muscle. Food is always better than a shake.
Protien is used to heal muscles which takes days, not hours so you need to always have plenty of protien in your diet, the most important times are as soon as you wake up, 1hour before your workout, after your workout, and before you go to sleep.
If your only protien intake is after a workout then you would be much better off drinking a quater of your shake, 4times a day.
but its better to have aprox 20 grams 6times a day