There is a perverse incentive when the client has a retainer to bill hours and makes excuses to line their pockets. Why tolerate this behavior? The customer is

There is a perverse incentive when the client has a retainer to bill hours and makes excuses to line their pockets. Why tolerate this behavior? The customer is always right, force them to stick to the contract or break away and take them to court if they are working on things outside of your contract and billing you.