This is a tricky question because the cool thing about Stardew Valley is that you create your own path in the game. You don't have to follow a strict method of progression, and different players will prioritise different areas of the game. However, the main plot takes around 52.5 hours to complete. If you're going for full completion, then you're looking at spending 147 hours to do so. The great thing about this is that even when you've 'fully completed' Stardew Valley, there's still plenty more fun to be had, and you can try out different methods of gameplay.