Typescript takes less than a minute to build, and basic PR validations (the simple regression, conformance, and unit test suites) add around 10 minutes of test running to that (to be fair, I can run those locally in just under two minutes, we just use slow CI boxes, and local incremental build and test can bring that loop down even more). The extended test suites that run on a rolling basis on `master` and on-demand on PRs can be much longer and take up to two hours to run (the longest extra suite being the DefinitelyTyped suite, where the CI system runs all of DefinitelyTyped's tests on both nightly and your PR/master and reports any changes). Technically, there is also a github crawler running periodically that rebuilds anything public and open source it finds with the latest TS and reports new crashes, and that's _constantly_ running, so I can't really say that has a fixed run time, per sey. Turns out the closer you get to building the world with your (build tool) project, the longer it takes, but the more realistic your coverage becomes.