As SpaceX is a company that is very focused on rapid reusability, low-cost operation and a philosophy of "the best part is no part", what repairs have to be done to the towers and general pad complex at their various pads every time they launch and do not have a rapid unscheduled disassembly within the proximity of the tower?
This question applies to both Falcon9 single stick and Falcon Heavy but not Starship as that is still very much so in development.
SpaceX talks about having rebuilt two launch pads in an article on https://spacenews.com/new-and-improved-florida-pad-ready-to-resume-falcon-9-launches/. During the rebuild of the SLC-40 launch pad, after the 2017 explosion of a Falcon 9 rocket, they optimized the launch pad to make it more durable. Much of the launch equipment, which was previously exposed to the launch, is now underground. They also reported that they made serious augmentation to the water system which prevents damage to the pad, as well as upgrades to the flame trench which helps prevent erosion of the pad. He is not specific with exactly what the upgrades were, but they are confident that these launch pads will support rapid launch rates. SLC-40 is not upgraded to support the falcon heavy, but will launch rapid Falcon 9 missions. The Falcon Heavy will launch from SLC-39 which was also restored. What I understand of SpaceX from articles such as this one, https://www.airspacemag.com/space/is-spacex-changing-the-rocket-equation-132285884/#:~:text=All%20very%20impressive.,%242%2C500%20per%20pound%20to%20orbit., is that they focus on simplicity. For example, they run on only two types of fuel which requires only one kind of engine. His ability to make his plans work with the system they depend on is what allows him to maximize optimization. He is a genius when it comes to understanding the system. He doesn't calculate things the same way that the system does in terms of his company. Musk is very secretive with his methods and plans because people keep stealing them (China, in particular); however, he does give general insight into his method, and the general idea is optimization at its highest standard. That is not the standard of our global economy, and Musk has capitalized on this. He makes the system work for him.
According to NASA (potentially outdated) they have to do a postlaunch check on the launchpad for safety. The water stream ejected during launch will greatly reduce launchpad damage, but I am unsure how much damage is caused. In the case of Starship, it would probably melt the launchpad without additional modifications to the pad, which is one of the reasons Sea Dragon would have launched from the sea due to the ridiculous amount of heat produced by the engine. You could possibly have a launchpad made out of Inconel (superalloy) which can withstand temperatures of 1300 degrees celsius.
