Another thing you can do in the future is to pay close attention to the photo of the model wearing the hat. If it's a large person with a big head, the directions will probably make it too long for the average user. I usually have the opposite problem. The hat always ends up too short. Most beanie type patterns don't cover the ears. I don't see much point in wearing a hat if your ears aren't warm.
If I see ears showing in the model, I know I have to knit about one or two inches more before I get to the decreases. You also have to take into account how wide you want your rolled up cuff to be, if you knit a hat like that. A one inch cuff won't stay put. I do a two or three inch rolled up cuff on hats to provide double warmth over the ears, but then we live in a cold winter climate. The traditional measurement for beanies is 5 1/2 inches from the start of your ribbed band until the decreases. I knit about 7 1/2 inches. If you knit a hat with a cuff, you will add the height of the cuff (two or three inches) to this. It depends on what type of decreases you do also. Here's a great decrease from Jimmy Beans. http://www.allcrafts.net/fjs.htm?url=www.jimmybeanswool.com/freeKnittingPattern_hat.asp I use this decrease for shaping the tops of mittens as well. This type of decrease runs about 1/2 an inch. Hope this helps you.
Source: Knitted all kinds of man caps for my adult sons and their roommates this past fall and winter.