You've no doubt heard many top players talk about how poker isn't a game you ever really "master." That's because every time you sit down to play you are necessarily presented with a host of new situations and opponents, forcing you to constantly revisit ideas as you gather new information and try (again and again) to form a winning strategy for the new circumstances you face.
It's possible to play poker without constantly studying your opponents and actively learning how best to combat them. It's even possible sometimes to win at poker without always being so attentive.