Answered Dec 10, 2017
An individual minimalist needs the items to efficiently do the activity of the moment.
The time-frame can also change.
Simple examples:
If I take a shower, I need jandals (flip-flops), a towel, fresh set of clothing, and bag for the dirty clothing, along with consumables like soap, and a bag for those.
If I am archiving paper documents, I need a computer, a scanner, and perhaps a shredder.
The total items which I need in general is the total that I would be using on a regular basis, for frequent activities. If I haven’t used a physical object in a year, then I probably don’t need it.
However, priorities can change with time.
For example, if I were to move to a new city, by bus/train/plane, the need issue would focus on reducing total volume to a couple of bags of the most needed, most important things.
In that temporary moment, I would take the computer, but efficiency would require getting rid of the bulky (but cheap and easily replaceable) scanner.
I think it is OK to start this journey by figuring out what you need. Not things to buy, but rather, which things you already have and use frequently, to help understand what else is surplus.