[Retric]

If you are sending stuff back up then parachutes are reusable, but heat shields are not. There might be an argument if you where landing thousands of rockets a day and had giant city's on mars. But, by that point you can just make more.

[phire]

Depends on the heat shield. The Space Shuttle's heat shield was designed for reuse (though in practice the tiles were so fragile that they needed extensive checks and occasional replacement before each reentry).

I notice that Spacex have designed their ablative heat shield to which can withstand hundreds of reentries to Earth without any replacement or refurbishment. Still technically a consumable, but I really doubt anyone is happy with re-packing and re-using the same reentry parachutes hundreds of times.

And that's reentries to Earth, where the entry velocity is 17,000mph and the atmosphere is 100 times thicker. Such a heatsheild can probably withstand thousands of Mars reentries at just 7000mph before replacement.