Disgustingly I now get clogged nozzles pretty often, with PLA agglutinated to the outside of it only one of several issues.
Note that in some cases the nozzle wasn't tight enough so PLA oozed out through the thread (another issue).
I always put a copper washer under the nozzle now and take care to clean the adjacent surfaces.
For reasons I don't know yet every once in a while extrusion becomes far too sparse, which ruins hours of printing and makes disassembling at least the nozzle, if not the entire toolhead a recurring necessity. When this happens, the print did not go well beforehand - it is quite brittle because of insufficient cohesion of layers (even with the print temperature already increased to 210-215°C):
A closer look also reveals that there are several brownish "mice poo" clumps woven into the part, mainly the support where the toolhead travels fast. Apparently, degraded PLA that was stuck inside the toolhead for quite a while ... what else could it be eventually?
Some time ago a "Commands/Set Toolhead Temperature" function was invented in FLUX Studio which comes pretty handy when taking apart the print head without much torque applied on the nozzle against hardened PLA residue.
But last time I did this the temperature ran away for reasons I don't know either ... first I noticed a strange smell from the toolhead, then fume rising from its underside - emergency! Time to pull the DC plug immediately. Has the sensor gone wrong eventually? How do I find out? Are there spares available? Second source? Or did beta Software trick me?
Anyway, I now got second grade burns on the toolhead plastic...