Is there any reason to cancel a construction instead of postponing it indefinitely? As far as I can tell, there's no refund for canceling.

Postponing unwanted constructions indefinitely. Huh. I never thought of that. It would increase flexibility. But then, there are things I already know I'm never going to care about, like when I forget about a forgeplanet for a few turns, and come back to find out I left it building a severely outdated version of my standard fleet corvettes. There's really not ever going to be a point in the game when I want that, except hypothetically to immediately refit it, so I don't really care about losing whatever production is invested in it.

DO delayed constructions save the production invested in them? In my experience it seems like it gets reset.