CNC Kitchen put 3D printed PLA into their composted for over three months. I don't remember the specifics, but results were underwhelming.

As someone who constantly prints temporary jigs and spacers, I'm interested in compostable filament. Bonus points if it is comparable to PLA in price.

There are a decent amount of plant parts that don't break down much at all in 3 months - doesn't mean they aren't biodegradable ultimately, although hoping for biodegradation as a way to eliminate litter is a nonstarter with this approach.

3 months? Most organics will not break down in that time. 6-12 months is recommended, and even then, not everything is broken down. I've had egg shells last 2 years or more in my compost bin.

I made no claims about the speed at which PLA breaks down, only that it does. Biopellets in reactors tend to last years.