[bskrobisz]

As a prime example of this, I'd point to the horrifying source for VVVVVV, a darling indie game of its time:

https://github.com/TerryCavanagh/vvvvvv (my favorite piece: https://github.com/TerryCavanagh/VVVVVV/blob/master/desktop_...)

(There was also discussion about it on HN before as well, if one is interested: https://news.ycombinator.com/item?id=22011358)

That said, refactoring for later gains might be wasted time if you have only a certain amount of scope planned for the rest of time, counter to the typical heuristic.