No Cooking for Your Altitude
Although this is a less common mistake, if you are a home baker, it is one you need to keep in mind. Those living in higher altitudes need to use a modified recipe in order to get the same results as everyone else. Too many bakers in high altitude locations always wonder why their baked dishes fail, but never double-check their recipe.
You can look up alternatives and baking times online, or you can go through a period of trial and error to help you account for differences. Once you get the sweet spot, then all of your baked dishes will come out perfectly every time you hit the kitchen.