A lot depends on how your home brew is stored. If you keep it at room temperature you will probably want to consume it within 6 months. If it's refrigerated it might last much longer. I had a bottle of home brew that was 3 years old in the back of the fridge. It tasted pretty darn good.
Another factor is the type of beer. Big beers usually require much more conditioning before they reach their peak. Barley Wines can take years to be at their best.
yup. It all depends on the style of beer and the level of hoppiness it should have. Beers lose their hoppiness after a while (It blends and mellows). If your a hop head you may want to cry now. If you're like me and a malt monster you wont care at all