Given the lifespan of plastic products I don’t think it’s so bad that people let their printers sit unused for extended periods of time. If you don’t have a useful/desired object to print I would rather they not make a plastic object that will last hundreds of years and cannot be currently recycled except by doing it yourself. I would be concerned that achievement hunters would in fact be motivated by your idea and will be printing benchies or other useless objects they don’t actually want to keep the streak up. Maybe instead you could make a handy way for the users to list their print wishlist so they could keep it running with stuff they need/want instead of the ritual.