Here are some of the most common reasons:

Q: All of a sudden I have a butter / pound cake problem. I have made the same recipe for years with good results, but suddenly my cakes have become heavy and not done in the middle.

A: Butter / Pound cake recipes that have been used for years don't seem to work anymore. These questions are not coming from amateur bakers but from experienced bakers who are asking, "What happened?" 

One of my first questions is "Have you checked your oven to be sure the temperature is correct? If not, check it with an oven thermometer."  If the problem is not the oven, then it must be something you must have changed -- ingredients, baking pans (different types), mixers (some are more powerful than others) or anything that's different.

Q: My butter / pound cakes look wonderful when they come out of the oven. Tall, light and a pretty light brown color. Once they cool, the top layer of crust collapses. This happens with all of my pound cakes regardless of the recipe? Am I beating too much air into the cakes?

A: Proper mixing of the batter will affect the outcome of your cake. Creaming the butter and sugar develops air cells in the batter, which helps give cakes their volume and texture. Make sure the flour is well mixed with the baking powder/soda to prevent uneven distribution of the leavener which can cause holes in the finished cake. (Some bakers sift the two after measuring, but it is not necessary. Add both to a medium-sized bowl and use a fork to combine the two). When adding the flour to the batter, do not overmix or it will produce too much gluten. Too much gluten causes a cracked and domed top. However, use a kitchen timer to help you keep track of the mixing time.

The way in which you add the eggs to the batter also affects the final outcome. Eggs should be added ONE AT A TIME, with the mixer speed on low. Make sure it's fully incorporated before adding the next egg. This step helps to incorporate more air in the batter and adds emulsifiers from the egg yolks, the most important step when making a pound cake. It results in a creamy mixture that holds in the air bubbles in, previously created through creaming. A cake baked with poorly emulsified batter will be grainy in texture, will look uneven and/or may even sink when baked.

Q: My butter / pound cake occasionally develops light spots on its smooth, golden brown crust. What happened? 

A: A perfectly measured and mixed batter will fail if your oven temperature is incorrect. An oven that is too hot during the early baking stage can cause premature release of the leavening, producing small blisters which collapse and form light spots on the crust. Therefore, invest in a good freestanding oven thermometer to accurately measure your oven. It is readily available from the grocery store.

Unfortunately, the only way to find out whether your recipe is bad is by trial and error; you've baked something several times and it doesn't turn out right. 

In this case, I always suggest trying a new recipe before you get too frustrated, feel like a failure and hate baking.