What quick checks do you do first on extrusion fading on long prints?

[NoponTora]

I had a long print last weekend that was looking perfect for the first hour, then it started doing that sad thing where the lines get skinny and the extruder starts sounding a little more clicky. I paused it, panicked a bit, and I honestly could not tell if I was dealing with a clog starting or heat creep slowly choking the filament. I ended up canceling because I did not want to cook the hotend for nothing.

When this happens to you, what is your quick mental checklist to tell the difference fast? Like do you check if the heat sink fan is actually spinning, try a cold pull, bump temp up a few degrees, back off retraction, or feel if the filament is getting chewed flat by the gear. I want a simple order of checks so I stop guessing and wasting half a spool every time it fades mid print.

 

[Kirkis_Elf]

First thing I do is watch the spool path. If the spool is snagging or the filament is dragging, it can sound like a “clog” but it’s really just underfeeding. After that I check the idler tension and if the drive gear is packed with plastic dust.

 

[Alan]

I like your idea of an order of checks. For me the first two are always fan and filament path. Fan dead or clogged intake can look exactly like a clog later in the print. Then I check if the spool is snagging and adding drag. Only after that do I touch settings like retraction and temp.