The intention is to need minimal to no replacement between flights. Part of the purpose of these tests is to figure out how to do that.

The tiles themselves work fine, but how to best mount them? where do you need them? Can you make them thinner? do you need anything underneath? what kind of gap do you need between tiles? Those are the things they're hoping to understand in these tests.

The Shuttle tiles were technically reusable AFAIK. The issue was that they were very fragile and the Shuttle for the most part could not tolerate any heat getting through the tiles (being aluminum), so every flight needed to have a perfect heat shield. Starship is a bit better on that end, as stainless steel is a lot more capable of tolerating heat and I think the tiles are a bit less fragile. Still, would be ideal to figure out how to not drop any tiles.

> Shuttle tiles were technically reusable

Would note that Shuttle tiles were never mass manufactured. The Shuttle’s shape meant lots of unique tiles. And its lack of mass production meant each tile was basically an artisanal object.

SpaceX aims to reüse tiles over many flights. But even if some tiles need replacing after each launch, that doesn’t tank Starship per se.

> every flight needed to have a perfect heat shield.

Which is a little easier to do when your craft is shaped like a plane and not a simple cylinder. The loading and positioning were easier to model and then achieve in flight.

The shuttle also flew with repair kits and glue that could be used in a vacuum. The astronauts could perform an EVA and work to replace damaged tiles and there were published plans on how to do so. NASA unfortunately figured out very late that using the Canadarm to image the bottom of the shuttle immediately on achieving orbit was extremely necessary given the icing problems of the external tank.