As TypeScript projects grow in size and complexity, compilation speed can become an issue. Some of the main culprits behind slow compilation times include large or deeply nested type definitions, extensive use of `any`, and inefficient configurations in `tsconfig.json`. To address this, enabling `incremental` compilation is one solution, which caches previous build information, speeding up subsequent builds. Additionally, using `tsc --build` mode with project references allows you to split large projects into smaller, independently compiled modules. Removing unnecessary `strict` type checks, optimizing `include` and `exclude` paths in `tsconfig.json`, and keeping dependencies up to date also help in reducing build times. For projects with complex types, precomputing some types or leveraging libraries like `typebox` can further improve performance.