It really depends in coding style. For example, I always like to write the smallest possible change to address a feature and bug fix that's testable, then I start writing unit tests, then back to code, then back to unit tests and so on. So it's not uncommon to do a lot of incremental builds (but yeah 30/hour is on the high side). Sometimes this is not feasible, e.g. working on a complex component which has a simple public API but does a lot of heavy lifting internally - in that case it takes a while to get to a testable change.
