The 3D printer arrived and, as warned, the first thing I printed was the little calibration cube that ships with every printer, and the second thing I printed was a tangle of plastic spaghetti welded to the bed. Welcome to the hobby.
I went with a Bambu Lab A1 Mini, partly because everyone said it just works and partly because I wanted to start from "it works" and learn the failure modes from there rather than fighting the machine and the slicer at the same time. For the most part the praise is earned. It auto-levels, it flow-calibrates, and the first benchy came off clean enough that I was suspicious.
The failures, when they came, were educational in the way only failures are. The spaghetti print was bed adhesion: a tall, thin model with a small footprint, and somewhere around layer forty it let go, the nozzle kept extruding into thin air, and I came back to a bird's nest. The fix was a brim, which is just a few extra outlines of plastic around the base to give it more grip, plus actually cleaning the build plate. Fingerprints are grease and grease is the enemy of the first layer. A wipe with isopropyl alcohol fixed more problems than any setting I changed.
The second class of failure was stringing: fine hairs of plastic strung between the towers of a model like cobwebs. That's retraction and temperature. The printer pulls the filament back slightly when it travels so it doesn't ooze, and if the hotend is running a touch hot for the material it oozes anyway. Dropping the nozzle temperature five degrees and letting the slicer's defaults do their job cleared most of it.
A few things I'd tell myself a fortnight ago. The first layer is everything; if it's down clean and squished nicely onto the plate, most of your prints succeed, and if it's not, nothing downstream saves you. Watch the first layer go down before you walk away. A clean plate beats a fancy setting. And the dramatic-sounding failures, the spaghetti, the warping corners, the print that detaches and gets dragged around, are nearly always adhesion or temperature, the two least exotic variables there are.
I haven't printed anything useful yet. I've printed a cube, a boat, a bracket that came out 2mm too small because I didn't account for shrinkage, and a respectable amount of waste. But I can already feel the shape of the thing: it's not a magic box that produces objects, it's a machine with about five variables that all matter and a strong opinion about a clean first layer. That's a tractable number of variables. I can work with that.