I think triple entry accrual accounting needs to be used to track the finances. Rather than being surprised about the results, one should plan the financial statement to achieve the results we want.

Think of the initial investment as an Initial Public Offering. All that goes into gear which all starts to depreciate over 5 years. Some gear we use the whole 5 years. Like a sleeping bag. Some we use less like those boots in the back of WD's closet.

Gear that doesn't get used for whatever reason incurs a capital investment by the business to replace it. There would have to be income to the business (meaning the backpacker would buy a secondary offerig) which would then be spent on more gear.

Simple measuring the cost per pound is not enough without some measure of when it's likely to be replaced. My cookset lasted maybe 15 nights before I stopped using it. Because it was heavy and inexpensive, the cost per pound is low, But the cost per use is high.

If this all seems complicated, all you would have to do is hire a backpacking financial analyst. And probably an accountant to do your taxes.