You have stated that 1) you make far more than you need; 2) the workload is too high and that 3) consistency and response time are important to the client. If

You have stated that 1) you make far more than you need; 2) the workload is too high and that 3) consistency and response time are important to the client. If you are truly concerned that taking time off will lead to problems with the client, then the solution is to hire someone to help you. But take a vacation before you go nuts.