ok, if you're not making your daily need in protein by way of a solid and balanced diet, then you can suppliment with a shake.
I generally don't suppliment with a whey shake. I'll use solid food sources such as cottage cheese, yogurt, tuna, beef, etc.
Find good sources of protein dense food. White Albacore tuna is awesome! A 3oz can of COTS white albacore is 21g protein.
A 1/2cp cottage cheese is 12g protein.
Milk is 1g/fl oz.
Yogurt (at least mine) is 11g/1cp.
The dairy products are 80% casein and 20% whey.
Casein is a slow digesting/metabolizing protein, better in the long run for feedings. Whey is best PWO.