Let me start off by saying "One size does not fit all OR everyone". Rock, Pebbles, Sand theory of Prioritization does work for some, but most people do not have a prioritization method at all and even if they do it may not necessarily work for them.
So, lets try something new!
Disclaimer: I know how to use this well and when not to use this method, it comes naturally and has worked very well for me and can greatly boost your productivity, but don't overdo it. Knowing the limits and pros and cons of every method is a must.
1) Lets say you have 3 types of tasks you need to do daily (ignore Impact for now)
Sr. No Priority Time_Required(each task) No_of_Tasks
1 High 2 hrs 1
2 Medium 1 hr 3
3 Low 15 mins 6
most folks will pick up the the work considering descending order of Priority (High -> Medium -> Low). The reason is psychological, we tend to give a lot of importance to tasks with higher priority.
But is it the best way to do things?
I usually use a reverse psychology trick to get the brain to work more efficiently. The human brain subconsciously always thinks that more number of tasks done = more productive and less time required to think about what else needs to be done / less stress.
Hence I end up usually reversing the order. (Low -> Medium -> High) . Lets see how it helps
By the end of 3 hrs
following (High -> Medium -> Low) you would have completed only 2, tasks, your brain tells you that you still have 8 tasks to complete.
following (Low -> Medium -> High) you would have completed 7.5 tasks, now your brain tells you that you only have only 2.5 tasks remaining.
Even though the time required to complete the tasks is same regardless of order used, you will feel much more fresh and ready to tackle the remaining tasks.
Now what if I change the equation to say that there is 1 Critical task (the highest priority level) that takes 4 hrs. Would you still follow the same method?
=> This is where I would not use the above process, most likely the Critical Task will take priority for me after which I will go back to (Low -> Medium -> High).
Again; understand the context and apply this method, as eventually we need to "Use the right tools/processes for the right job".