Why the cheapest upgrade can still delay your next purchase
An upgrade spends money immediately and earns the difference gradually. Compare its extra income with its price, then include the time needed to afford it. Dividing price by the new total income makes the return look faster than it is: you were already earning money before buying.
In the worked example, you start with 500 and earn 100 per minute. A 1,500 upgrade raises that rate to 180. It takes 10 minutes to afford. Recovering its price relative to saving takes another 18.75 minutes, so the two paths meet 28.75 minutes from now. At minute 30, saving gives 3,500 and upgrading gives 3,600. Yet the 5,000 target arrives at minute 37.8 with the upgrade, compared with minute 45 by saving.
Measure the result you need
For pet income, measure the whole setup before and after replacing a pet. A new pet’s displayed income is not all extra income if it displaces an existing earner. For movement or training upgrades, use time saved as a separate decision: a Speed increase is not automatically an equal percentage increase in cash. You can use the planner only after estimating its effect on your earning rate.
Try a conservative rate as well as your optimistic estimate. If a purchase only wins under the optimistic case, saving may suit a short session better. An upgrade that unlocks a new area, a collection reward, or a play style you enjoy has benefits this currency comparison cannot price.
Assumptions and formulas
Both earning rates stay constant. You buy immediately when you can afford it, earnings continue while saving, and the upgrade takes effect immediately. There are no additional purchases, randomness, trading fees, offline earnings, or resale proceeds. If you reach the target before the purchase, the first time you reached it is shown.
Wait time = max(0, (price − balance) ÷ current rate). Catch-up time = wait time + price ÷ (new rate − current rate), when the new rate is higher. The comparison is an estimate from your inputs, not a promise of game rewards.
For random hatches use the odds calculator. For a repeated farming cycle use the farming ROI calculator.