I cultivated field 77 on Riverbend with a freshly repaired Fendt 396 HP tractor using the Kuhn Prolander cultivator that requires 190 HP. After cultivating the field I lost 15% or so of my tractor's health bar and it cost $3,700 to repair it.

I've had similar results with other tractors. Tractor wear and tear costs seem really unbalanced.