[Dalewyn]

Space Shuttle (and now SLS) SRBs always dropped into the ocean for recovery after the fact.

[mikepurvis]

I think it’s actually a bit more nuanced than that, see:

https://space.stackexchange.com/a/45894

Basically the SRB had multiple modules and some were more reusable than others, so some got recovered and refurbished a lot more.