DIY is sold as a cost cut. Often it is a cost transfer.
The unaccounted costs: tools and equipment you do not yet own, supplies bought in quantities larger than you’ll use, ingredients with shelf lives that expire mid-batch, the learning curve and its trial-and-error tax, and the storage burden of single-purpose gear afterwards. Each can quietly exceed the price of just buying the finished good.
The source’s canning example is sharp: she wanted to preserve produce, bought all the equipment, learned the process, canned a few things, and dropped the practice. The fixed costs were paid; the recurring savings never materialized. Same with homemade almond milk — it tastes better, but a five-day fridge life vs. store-bought longevity makes it a quality choice, not an economic one.
The honest test is recurrence. DIY pays when (a) you use the output frequently, (b) the per-batch waste is near zero, and (c) the tools already exist in your kitchen or shop. Pancake mix, multi-purpose cleaner, bulk staples: pass the test. Canning, soapmaking, niche craft: usually fail.
The Reddit line the source quotes is worth keeping: “If you don’t already have nearly all the necessary supplies on hand, it will cost you more to make it yourself.” The pleasure of making is a legitimate reason to DIY. The savings story is the part that should be audited.