The following contracts should be written: Once you agree to do something, people usually expect you to do it – but are you legally obligated? However, you can create, modify or modify the terms of the contract non-verbally through your behavior. For example, if you agree to give 100 items a month to a company at a certain price, but accept less money over time, you can waive your right to the initial amount, without ever indicating it directly, since you continued to provide the number of items and accepted any payment. . . .