I've seen several Q&As on recycling and reusing plastic from failed prints, but what have you done with the last few meters of filament? I've been keeping the ends of PLA (or sections I needed to cut) to maybe use for friction welding pieces together, but I only need so much for that. I've considered just shoving the last bit in the tube and using a new roll to push it through (so long as retractions aren't necessary).
This is especially a concern for more exotic filaments where friction welding isn't useful and the price is higher for that 1m section (something like Copperfill).
Note: I have a Bowden extruder. I imagine this is less of an issue with DD extruders.