Cap your take so the customer always feels the win
Costco has a written rule. Gross margin on branded goods is capped at 14%, Kirkland at 15%. Walmart runs around 24%. Target around 28%. Buyers cannot price an item above the cap without sign-off from HQ. When a vendor improves the product or cuts cost, the gain doesn't widen Costco's margin — it flows back into a lower shelf price. Sinegal once pointed out you could raise a bottle of ketchup from $1.00 to $1.03 and no customer would notice. Three percent on every item would add 50% to pre-tax income. The whole company exists to refuse that trade. The result is a shopping experience where every random item is priced honestly, and the customer can stop comparing.
The play
Pick the metric that most signals "we take the right amount, not the most we can extract" in your category. For SaaS, a per-seat cap. For marketplaces, a take-rate ceiling. For DTC, a sticker test where any item over $X gets re-justified. Write the cap down. Defend it when growth tries to push past it. Customers feel the cap across every product they touch — that's where its power comes from.