I've been looking for just this one bit of info, in all the press: exactly how much of the Falcon Heavy is recoverable and reusable? Obviously not the fuel, but is all the hardware recovered? If so, isn't that truly remarkable?
The plan is that the two side boosters will land back in Florida at LZ-1 and LZ-2 as the first flight did. These are reusable, in fact both boosters in the first flight of Falcon Heavy were on their second flights. (CRS-9 and Thaicomm-8 missions were their previous flights).
The center core is planned to land downrange on the ASDS OCISLY and in this case that failed.
In all cases, the interstage that houses the grid fins and the cold gas thrusters is recovered with the first stage. In the post launch press conference Musk suggested that recovering the side boosters was most important as the new Titanium based grid fins are expensive, hard to make, and thus recovering them was important. No doubt they will fly many more times, even if the core booster itself does not fly again. (Block 3 boosters only fly 2 times right now, and these both have now had 2 flights)
The second stage is completely expended at the moment. It is considered unlikely to be recoverable in the current design.
The fairing, which covers the payload is in the process of being made recoverable. SpaceX has been trying to land them, which they have recovered partially, but are not there yet. Musk expects within the next six months to figure this one out.
They even built a catcher ship, which is currently in Port of LA in the Pacific that they hope will make it work better. It looks very cool.
When launching a Dragon capsule, the capsule itself is recoverable, but the trunk that holds unpressurized cargo is discarded. The nose cap is lost as well.
The Dragon V2 is expected to have the nose cap on a hinge so it is no longer going to be thrown away.