I looked at the trees in my back yard and noticed they needed some trimming. Since I have access to a chain saw, it didn't seem like that big a deal. At the completion of my job today, I thought I should write down what I learned. I made it into a simple formula I call the "2-3-4 Formula".
Take the number of times you think you will fill up the pick up with your brush. Multiply that number by TWO. This is how many loads you will actually take!
Take the number of hours you think you will need to complete the tree trimming project. Multiply that number by THREE. This is how many hours you will actually need!
Estimate how tired you will be when you are done. Multiply that number by FOUR. This is how tired you will actually be when you are done.