Farm units should be ranked by when their net income becomes positive, not by the largest end-screen cash number. Tycoon is a commonly discussed Retro Tower Defense economy example, but current cost, income, upgrade path and alternatives must be read from the live card. A farm can be excellent in Endless, optional in Normal and actively harmful in a short Hard badge attempt.
Economy tier bands
This intentionally avoids a fake permanent S-to-D name list. Public official data does not expose a complete live income table, and patches can change the ranking immediately.
Calculate payback
Write down placement plus upgrade cost. Add income actually received and subtract the investment. The first payout where the result reaches zero is payback; income after that is net gain. Also count opportunity cost: if the farm delayed a necessary carry and lost the run, its theoretical later income has no value.
For a simple comparison, track net cash gained ÷ elapsed minutes under the same map, mode and stopping point. If income arrives per wave, compare equal wave counts as well as real time. Include sell value only when you really plan to sell at that point.
Safe economy timing
Place the opener and reach the minimum stable breakpoint first. Keep emergency cash for an unexpected property or second lane. Buy one economy step, watch the next wave, then expand only if the defense remains comfortable. Put farms on outer legal tiles so they do not consume carry positions or support radius.
In Endless, decide when economy will stop. Once cash is no longer the main constraint, farms may be converted into scaling damage or control. In Hard or Insane, a second defender can have better real payback because it prevents a reset.
Compare missions and account progress
Sometimes the best economic action is not a farm tower. A mission that awards the resource you need, an event objective or a faster short clear can beat a fragile long run. Track Tix, EXP and event currency separately; do not treat them as interchangeable cash.
Farm mistakes
- Buying economy before the opening lane is stable.
- Comparing gross income instead of net income.
- Ignoring board space and support geometry.
- Copying Endless timing into a short badge run.
- Upgrading every farm evenly without checking the next payback point.
- Keeping farms after cash stops being the limiting resource.
Use the best loadout for role balance and the Endless loadout for a sell plan. The best farm tier is always conditional on survival time.
Example payback log
Create four columns: wave or minute, total invested, income received and net value. Add placement and every upgrade to investment. The first entry where income equals investment is payback; later entries are profit. If selling is part of the plan, add sell value only at the real sell point.
Run the same map once without the farm. If direct defense reaches the objective faster or avoids a reset, that saved run is economic value even though it does not appear as income.
Decide when to stop farming
Ask whether cash or board strength is now the constraint. When the final upgrades can already be purchased on schedule, more economy may add no practical value. Sell farms only after the replacement placement is ready, and keep enough emergency cash to survive the transition.
In co-op, nominate one economy owner and agree how the team benefits. Multiple players independently farming can leave every lane weak. Record party size because a timing that works with shared defense may fail solo.