Image via WikipediaIn GTD, David Allen discusses the 6 different levels of "horizon of focus". Why do we need different "horizons of focus"? All work has different levels of importance. Different people weigh things differently. However, all weighing decisions need to fit within one's perspective(s). And it's not merely importance, but the perspective themselves also help you actually DEFINE work from generic "tasks".
The metaphor used in GTD is one of altitude... from ground level, up to 50000 ft. In GTD, it's called "horizon of focus". The higher you are, the broader your perspective, but the less details you see. When you're at 50000 ft, you're looking at your entire life, but you don't see specific tasks any more, just general guidelines. On the ground, you have individual action items, but you can't see beyond the immediate horizon. In between, you have long term goals, short term goals, and so on.
The 6 levels "horizon of focus" are:
50000 ft / Purpose & Principles: review when you have a MAJOR decision to make, such as something that affects your life-long ambitions or beliefs
40000 ft/ Vision: review when you need long-term vision and direction, as in 3-5 years, or longer down the line.
30000 ft / Goals: review to ensure you are on your way to achieve your vision, think what you need to do in about a year or two.
20000 ft / Responsibilities: review to ensure you have balance in your life, this technically does not have a time limit, but it's actually ongoing... Are you taking on too much responsibilities, or too little? Is one of them overwhelming the others? If so, how to reachieve balance?
10000 ft / Projects: review for short-term commitments, from a week to several months
Ground / Calendar and Action items: review for dated and ASAP commitments
It's not really a "list", but areas you need to think about, on why you're doing something. Why are you buying your wife flowers? Because you love her, and you forgot last week. Is that more important than getting your car's oil changed? Absolutely! But if you don't "know" why you're buying flowers, and just wrote "buy flowers" vs "change oil of car", change oil would look more important! Buy flower for wife is like a 20K ft responsibility task, whereas change oil in car is more of a project as in "keep my car running well", even though you may not think about it that way.
Thus, by examining the WHY, through different levels of perspective, you have determined the importance level of a task.
For example, when you think about changing jobs, or get married, or such, it's a question at the 50K perspective. Your principles and purpose will guide you. Do you believe you are here to achieve something in life? Does this action item contribute to that purpose/principle? Desire to be financially free is the 50K level. Major life decision, of course.
At 40K level, think 3-5 year goals. Does the task contribute to the long-term vision? What are you doing to support that vision, perhaps "achieve 50% passive income to expenses ratio"?
Shorter term is 30K level. Decide on real estate, stock investment, or start a business would be on this horizon. Think 1-2 years. Does the task contribute to the goals you have at this level? Like "Grow real estate holding to 2 million"?
The 20K level is what is sometimes referred to as the work/life balance, but it goes much further than that. This is where you decide how you balance your various responsibilities, like investor, family man, employee, father, spouse, etc. Does the task significant tilt the responsibility toward one side or the other? Can you compensate? What is the "price", so to speak? Can you "afford" it?
The 10K level is your shorter-term commitments, like a week to few months. One example is "invest in one single-family or duplex within 6 months". Does the task fit within your short-term goals?
Ground level would be your actual action items. For financial freedom, it'd be something like "research one property this week" or "research 5 stocks this week"
By being aware of these levels, your decision on what is important, and what is not, can be justified properly. In other words, they help you define work, not just determine the importance.
Once you have full understanding of the different horizons of focus, you can use them to help you define work, as well as classify work as being important or unimportant. Then it is much simpler to decide whether to work on something or not.