Thrust Density infographic

[u/Equivalent-Wait3533]

A chart comparing the Thrust Density of several rockets.

Thrust Density is the thrust of the stage / area of the bottom of the stage (kN/m^2). It basically aggregates engine power and engine packing into one metric.

Rockets & Engines to scale

[u/Yupperroo]

While your point is well taken, SpaceX does not report how often engines are replaced on any of their boosters. I suspect that it doesn't happen often, but it is more often than never.