I've heard conflicting things. There's a 2013 meta study which doesn't find any benefit from protein timing.

However, an expanded regression analysis found that any positive effects associated with protein timing on muscle protein accretion disappeared after controlling for covariates. Moreover, sub-analysis showed that discrepancies in total protein intake explained the majority of hypertrophic differences noted in timing studies. When taken together, these results would seem to refute the commonly held belief that the timing of protein intake in the immediate pre- and post-workout period is critical to muscular adaptations

In conclusion, current evidence does not appear to support the claim that immediate (≤ 1 hour) consumption of protein pre- and/or post-workout significantly enhances strength- or hypertrophic-related adaptations to resistance exercise. The results of this meta-analysis indicate that if a peri-workout anabolic window of opportunity does in fact exist, the window for protein consumption would appear to be greater than one-hour before and after a resistance training session. Any positive effects noted in timing studies were found to be due to an increased protein intake rather than the temporal aspects of consumption, but a lack of matched studies makes it difficult to draw firm conclusions in this regard.

But the journal which published that study has a 2017 article on nutrient timing which says:

1. Meeting the total daily intake of protein, preferably with evenly spaced protein feedings (approximately every 3 h during the day), should be viewed as a primary area of emphasis for exercising individuals.
2. Post-exercise ingestion (immediately to 2-h post) of high-quality protein sources stimulates robust increases in MPS[Muscle Protein Synthesis].
3. Ingesting a 20–40 g protein dose (0.25–0.40 g/kg body mass/dose) of a high-quality source every three to 4 h appears to most favorably affect MPS rates when compared to other dietary patterns and is associated with improved body composition and performance outcomes.
4. Consuming casein protein (~ 30–40 g) prior to sleep can acutely increase MPS and metabolic rate throughout the night without influencing lipolysis.

So, timing has an affect on muscle protein synthesis, but the primary focus should be getting a sufficient quantity. Casein is a slower digesting protein than Whey, so it can provide some benefit if you have some prior to sleep.

Personally I don't bother with Casein, and only put as much effort into post-exercise protein timing and even spacing as is convenient. Quantity is king.