Concerning any sort of business agreement, it is always best to “get it in writing”. No matter what kind of business you do, to the extent the parties to a “deal” can 1) define their expectations clearly and specifically; and 2) anticipate potential problems and contingencies and outline how their occurrence will affect and/or change those expectations, they are going to be better off. A well-drafted, comprehensive contract is a great tool for minimizing the chances of litigation down the road, and it is a lot cheaper!