They have occasional landing failures (one this year, two last year), and still do launch expendably every once in a blue moon, so they'll likely need to build a new one every once in a while until the end of the program is in sight.

(It looks like they have very few customers anymore that insist on a new-build booster -- the fussiest had been the US government, but at this point, NASA is accepting reused boosters for human spaceflight, and the NRO has also accepted one for a mission last year. As far as I know, no one has publicly said they'd rather their booster has a test flight yet.)

I forget what its called, but if something is gonna fail... its most likely to fail on the maiden launch (or like first 100 miles for cars)

Bathtub Curve, https://en.wikipedia.org/wiki/Bathtub_curve

Iridium was very important in their booster reuse program, they were early supporters. Matt Desch (thier CEO) was a big supporter. https://twitter.com/IridiumBoss

https://spacenews.com/iridium-open-to-reused-falcon-9s-if-it...

If we assume 10 as the max. The have at least 40-50 flights left in the boosters the have. Now some of those a reserved for NASA/DoD and while they can be reused, they will likely only be reused for those costumers. So in practice its a bit less.

If they can go significantly beyond 10, say 20, they have years of booster left if they want to.

I think they might only need to produce like 5ish or so more and that should mostly be fine until Starship destroys the market for the F9.

Saw from one of the Space reporters on Twitter that this booster will do an April launch of another Starlink mission.

Wouldn’t they want to continue building them to some extent just so they don’t lose the institutional knowledge of how to build them? Or is the expectation that Starship will render it obsolete soon enough?

Some clients request brand new boosters, and some mission profiles require losing the booster. I think there is no danger of them ceasing to build booster.

They produce a new non reusable second stage for each launch which is constructed in a similar manner to the first stage (just far smaller) so they are keeping their skills current.