Depend the rest of your diet (calories, macros and stuff)

If you already manage to get 0.8g of proteins per pound of body weight daily with real food tho, powder is useless.

if you are serious about bulding muscle mass you first want to calculate your training day and rest day macros when you do this you will then need to try to build a diet to help get all the nutrients you need then you use a suppleent to help you get the ammount of protein you need usally though i only take it after work outs but thats because i dont have enough money to get enough for off days.