Use-Up-Reel-Ends Box

Out with the old reel, and in with a new one! Some problems that come with printing parts using the last bit of plastic in a reel have been bugging me for a while, as it's usually difficult to judge whether something that you want to print will use up all the remaining plastic, and how it does so.

You can take an approach of printing something so large that there isn't quite enough plastic to complete it, and the object gets truncated, but there are very few basic printer parts with a large unnecessary section at the top for your uncertainty to fall within, so most of the time one can't be sure if the printer will run out of plastic before finishing a crucial section.
You could also run a few print jobs of very small parts, but then you either have a significant length of waste plastic at the end, a final print of small parts that may not be useable if you run out halfway through, or you end up printing one of Zeno's paradoxes to try and avoid either of those fates.

I've tried t