It depends on the sophistication of the client. I don't overwhelm them with each and every data input worksheet like Turbo Tax (128 pages for an itemized return). I make sure that the client understands what each form or schedule is and how that information relates to their tax return. A good example is the Student Loan, Or Tuition/Education Credit worksheets. Another important worksheet would be income and expense allocation for multi-state returns.
For Sch C, E, F taxpayers their Federal and State depreciation schedules are included. Unfortunately I have to explain the state differences because of my home state of MA.