Buy It For Life — Breakeven Calculator

How this works: The breakeven price is solved so that the quality item's net cost (purchase price minus the present value of its resale proceeds) equals the present value of all future cheap purchases (a growing annuity discounted at your return rate). Because both sides scale with price, the equation resolves to a closed-form: P = annuityPV / (1 − retain × ((1+appr)/(1+rate))^n). The portfolio chart uses the actual quality price as the shared starting capital: the cheap scenario invests that sum and withdraws each year's inflation-adjusted cheap cost; the quality scenario converts the capital into the item (shown at its realisable value — purchase price × retained fraction — from day one, then appreciating from that base).