When large payments are due and you are depending on cashing out stocks to cover the costs, experts say that planning ahead can make all the difference. While stocks are always changing, it is important to watch approaching dues so that you can transfer money into safer investments. Planning 12-18 months in advance is ideal, but planning does not have to take that much time as long as you know which shares you need to sell. It is also recommended that you research which stocks to sell and only cash out on the ones with the least embedded growth. If you prepare early on, there is little need to worry about dropping prices.