Estimate before buying; measure afterward
Before purchasing an upgrade, you can measure your current rate, but you cannot measure that unpurchased upgrade's result on your account. Use a clearly stated assumption for planning, or leave the expected result unknown.
After a purchase, compare like-for-like observations to review the outcome. Do not describe a before-purchase guess as a tested return.
A short coin-payback time is one decision factor, not a universal rule for what every player should buy. This guide does not establish a verified first-upgrade ranking.
Open Upgrade Planner