( e.g. Stuff describing attempted assistance, or BIT recommendation )
While trusting memory might be fine, it might also leading people down a false path with what is being set up..
Experts recommend an ancient visual-spacial system with a limited number of categories, and discourage proper expansion.
This is a recipe for disaster with a large enough set of possessions.
They should be setting up a system that does not rely on memory - with inventories / indexes / maps / any records, reviewable and/or searchable, like my computerized system, or at the very least, a written inventory on paper..
Doing otherwise has no chance of working, even with a relatively modest "large enough" set of possessions, and no wonder it hasn't been effective.
Memory is guaranteed to fail - either by forgetting + infrequent use, or by insufficient memorization ; and the system proposed by experts is guaranteed to run into all sorts of limits, long before organizing everything, unless radical discarding is also applied, which is what the experts also expect, encourage and count on.
So this system only works out in cases of surrendering and becoming a "regular person", a borderline minimalist.
For comparison, I am myself using a system, tested and proven over the years, with a computerized inventory and around a thousand boxes.
This is what I'm dubbing mine - a thousand box method - to be contrasted with the 3-box / 3-pile method commonly presented ( keep, discard, donate/resell or whatever ).
I trust my memory - but only for containers / categories in regular use, or sufficiently memorable ones. For the rest, I rely on written / computerized records, and/or container labels.
It is not reasonable to expect anyone to remember every detail of what they store where, especially those possessions / categories in infrequent use.