If you're trying to increase your weight and muscles then you should drink between 1 to 2 protein shakes per day.
I would not drink anymore than 2 protein shakes per day because you could get too much protein intake which could be bad.
If you're trying to lose weight then drinking only one protein shake per day or 1 protein shake every few days would be enough.
Protein Shakes contain calories so if you're trying to lose weight then you don't want to drink too many protein shakes because it can cause weight gain.