PLA, PETG and TPU show up side by side in buying guides so often that it is easy to think of them as three points on the same scale, easy to hard, cheap to expensive. They are not. PLA and PETG are rigid plastics. Bend a printed wall far enough and it cracks or stays bent. TPU is an elastomer: bend it and it springs back, the same property that makes a rubber band a rubber band. The question worth asking before buying a spool is not which of the three prints easiest. It is whether the part needs to flex and recover, or just needs to survive being dropped.
Shore hardness is the number that actually matters
TPU is sold by Shore A hardness, a scale that runs from soft, gummy materials around 60A up to firmer grades near 95A, with some blends pushing into 74D territory that starts to feel closer to a rigid nylon than a rubber band. 95A has become the default recommendation for a first TPU spool, and for a practical reason: it still flexes enough for phone cases, printer feet, cable strain relief and gaskets, but it is firm enough to feed through a Bowden tube without buckling, where softer 85A or 60A grades usually need a direct drive extruder to print reliably. PLA and PETG do not have a Shore A rating worth quoting, because at room temperature they behave as rigid solids rather than elastomers. That is the real dividing line: TPU deforms and returns to shape under load, PLA and PETG deform and either snap or stay deformed.
Printing TPU is a different job, not a harder version of the same job
TPU 95A prints in a similar temperature window to PETG, commonly cited around 220°C at the nozzle, but almost everything else about the process changes. Speed drops hard: TPU needs roughly 20 to 30 mm/s while actually extruding, well under typical PLA speeds of 50 to 60 mm/s or PETG’s 40 to 60 mm/s range, because the material’s own elasticity fights the extruder if it is pushed too fast. Retraction shrinks too, down to roughly 0.5 to 1.5 mm, compared with the 1 to 6 mm ranges common for PLA and PETG, since a soft filament that gets yanked back through a long retraction move tends to buckle inside the extruder rather than retract cleanly. FirstLayerGuide’s own TPU print settings guide covers the full tuning process; the point here is narrower: TPU is not PLA with worse manners, it is a different material family that happens to share a nozzle temperature range with PETG.
What flex actually buys you over a tough rigid part
PETG already has a reputation as the tougher, more impact-resistant step up from PLA, and for parts that just need to survive a drop or daily handling, that toughness is often enough without paying TPU’s printability tax. Where TPU pulls ahead is anything that needs to compress and rebound under repeated load: gaskets that need to seal against an uneven surface, printer feet that damp vibration, phone cases that absorb an impact by deforming instead of transmitting the shock to the phone, or straps and hinges that flex thousands of times without fatiguing. A rigid PETG part under that kind of repeated bending will eventually crack at the flex point. A properly printed TPU part is designed to take that motion indefinitely, the same reason a rubber gasket outlasts a plastic one in a sealing application.
Where PLA still wins
None of this makes PLA obsolete. For prototypes, decorative prints, or anything that never sees mechanical load, PLA remains the easiest and fastest material of the three: it prints hot enough to be forgiving, cools fast enough to hold sharp detail, and needs none of TPU’s slow speeds or PETG’s slightly stickier bed adhesion habits. The choice between the three is not a ladder from beginner to advanced material. It is a decision about what the part actually has to do: look right and print fast, survive daily wear without flexing, or flex and recover under repeated load.
If the part cracks under PLA and still fails under PETG’s added toughness, that is usually the sign flex, not just strength, was the missing property all along. Buy TPU for that job specifically, expect slower prints and a direct drive extruder to make the process painless, and keep PLA and PETG in rotation for everything that only needs to be rigid and tough.