The last factor to consider when drilling down the data is “data availability“.
It seems so natural to care about its availability but it is extremely important and practical to think of it before studying what axis you apply for the drill-down.
You may be able to consider any ideal axis to break the data but you may end up with giving up the idea during the analysis. In reality you cannot obtain all the data you need, especially if you are not an analyst or do not belong to such specialized organization for analysis who can afford to procure the data from outside, you have to manage/struggle to reach required outputs only with already existing (i.e. available) data at hand.
Before you notice the fact such data does not exist at hand at the end of the analysis, you should consider whether you have the data available to apply for the axis you choose.
My suggestions at my lecture and trainings are always very practical as above. They will help you save your time and efforts when you analyze business data.