There's a specific moment every small-warehouse owner knows. Two team members have the spreadsheet open. One updates a stock count at 10:47 a.m. The other closes the file at 10:49 a.m. and overwrites the change. The next day, the picker can't find the SKU the system swears is on shelf B-14, because the spreadsheet lied — it lied about stock on hand, it lied about who moved what, and it lied about when. No one notices until a customer emails about the missing order. This is not a story about Excel being bad. Spreadsheets are one of the most valuable pieces of software ever shipped, and they carry small warehouses further than most people expect. The question in 2026 is not whether to abandon them — it's whether the work you're doing has crossed the line where a spreadsheet starts costing you more than a custom app would. This article gives you a concrete way to draw that line.…