By Orbital Team
A reusable first stage costs more to build than an expendable one. It needs extra propellant margin for the return burn, landing legs or a catch mechanism, grid fins or equivalent control surfaces, and structural reinforcement to survive reentry heating more than once.
That upfront cost only pays for itself if the stage flies enough times to amortize it below what an expendable stage would have cost per flight. The breakeven point depends heavily on refurbishment cost: a stage that needs a near full rebuild between flights barely beats an expendable one, while a stage that flies again after routine inspection changes the economics completely.
The number that actually matters is marginal cost per flight once the fleet is mature, not the cost of the first reused flight. Early reused flights carry the amortized cost of solving reusability in the first place, which makes early cost comparisons misleading in both directions.
Second order effects compound the savings: a higher flight cadence spreads fixed costs like range operations and manufacturing overhead across more launches, and a proven, frequently reflown stage needs less requalification testing per flight over time.
The honest summary is that reusability is a bet on flight rate, not a bet on the hardware alone. A reusable rocket that flies twice a year is almost certainly more expensive per kilogram than an expendable one; a reusable rocket that flies weekly is a different business entirely.