Any system is designed using a particular set of assumptions about your work. The assumptions need to fit your situation.

For instance, the weekly/daily goals system works well when you have a number of concrete tasks to complete. But if your tasks are open-ended or contain only one task, then the system doesn't fit the task.

Your productivity system should counterbalance your worst tendencies.

• Fixed-schedule productivity corrects the tendency to work overtime constantly.
• Maintaining deep work hours is used to keep you focused on meaningful work.
• The most important task method works when you have a few difficult tasks that you need to prioritize.
• The Quadrant systems focus on important over urgent tasks.
• The Pomodoro system assumes you are procrastinating because the problem feels too big to get started. This system gets you to focus on the next chunk, not on the entire project.

Every system will create situations where it no longer makes sense to follow its guidelines. Then one should find a way of handling the exceptions without losing track of the original system.

• Ask if the exception to the basic rules helps you to buffer against an unproductive tendency.
• If the exception is made into a new rule, will it support the system you're trying to create?

A good productivity system should be productive, not just feel productive. A good productivity system that is working effectively should not feel like anything. It should just be holding up your routine.

• Feelings are not an absolute measurement. Relying on feeling productive creates a situation where if you don't feel productive, you feel like a failure.
• The feeling of productivity is often tied to a feeling of exertion.

When you're evaluating a productivity system, the right measurement to make is to find out if you're getting more done than you did last week/month/year.

Don't compare yourself against a theoretical possibility. Instead, compare yourself against your own past results.

A system shapes your existing motivations. It cannot give you motivation.

Many failures of productivity are a deeper problem of meaning and mission in life. People that tend to succeed with productivity systems already have meaning.