How often do you watch replays?

I’m trying to get better D3 Zerg. I think, like an instrument, using your brain in a RTS means you need practice. So playing is the best way to get better. What exactly does watching a replay help with in regards to getting better? If you could give it incremental value would you say 8-10 percent? Have any of you watched a replay and went on winning streaks or had big “aha” moments?