Most hobby FDM "the printer is broken" nights are not a broken printer. They are one of four problems. Check in this order before you start another 4-hour print.

1. First layer. If the skirt is patchy, stop. Wash the bed, re-level, slow the first layer. Reprinting on a bad first layer is how you waste a roll.

2. Temperature, not speed. Stringing, weak walls, and shiny-then-matte layers are usually 5–10°C off for the filament you actually loaded. Run a temp tower on that spool. Do not trust the profile's default.

3. The path is clogged or grinding. Clicking from the extruder means stop pushing. Heat, retract, cold-pull. Keep printing through a grind and you will need a new heat break.

4. Something shifted mechanically. Layer shifts and ringing after a nozzle crash are belts and pulleys, not the slicer. Tighten, then reprint a small cube — not the 12-hour model.

If it still fails after those four, it is usually something you cannot see in a photo: a lying thermistor, a bent gantry, or a board that drops steps under load. That is when a live look at the machine is cheaper than three more reprints.