When managing teams of "information workers", I believe the use of time sheets is indicative of a management failure. Here's why:

• If you have to rely on a timesheet to know what your staff are doing - you're doing it wrong
• If you can't trust your staff to work hard - you have problems a timesheet won't fix
  
• If you believe you have too many staff to manage - get more managers
• If you think anyone completes them accurately - you drank the kool aid
  
• If you think the time it takes to actually complete them accurately is worth it - you hate your staff
• If you manage your business from these inaccurate stats - you're making bad decisions
• If your senior people have PAs complete their timesheets for them - you're a hypocrite
  
• If you spent millions on a new timesheet system, but didn't make it any easier for the staff using the system - you just suck