Filament type determines print settings, strength, and where a finished part can actually be used — treating all filament as interchangeable is a common, avoidable source of failed or disappointing prints.
PLA, ABS, and PETG serve different needs
PLA is the easiest filament to print with, requiring lower temperatures and minimal warping, making it the standard recommendation for beginners and most general-purpose printing. Its tradeoff: it softens at relatively low temperatures, meaning a PLA part left in a hot car or in direct sun can genuinely warp or deform, and it's more brittle than other options under stress. ABS is more heat-resistant and impact-durable than PLA, suited to functional parts that need to withstand heat or physical stress, but it requires a heated print bed and enclosure to prevent warping and cracking during printing, and produces stronger fumes while printing, needing better ventilation. PETG sits between the two — more heat-resistant and durable than PLA with less warping difficulty than ABS, a reasonable middle-ground choice for functional parts without ABS's more demanding printing requirements.
Print temperature isn't a suggestion — it's tied to the material's actual chemistry
Each filament type has a specific recommended printing temperature range because that's where the material properly melts and bonds between layers without degrading — printing too cool causes poor layer adhesion and weak, failure-prone parts; printing too hot can cause stringing, oozing, or actual material degradation. Using a temperature setting suited for one filament type while printing a different one is one of the most common causes of failed or poor-quality prints, more so than most other setting mistakes.
Filament absorbs moisture from the air, which affects print quality
Many common filaments, including PLA and especially PETG and nylon, absorb moisture from ambient air over time, and printing with moisture-affected filament causes visible print defects — popping or crackling sounds during printing, rough surface texture, or reduced part strength. Storing filament in a sealed container with a desiccant when not actively printing meaningfully extends how long it stays in good, dry condition, particularly in humid climates where moisture absorption happens faster.
Specialty filaments trade ease of printing for specific properties
Flexible filaments (like TPU) produce genuinely rubber-like, bendable parts but print more slowly and require more careful printer settings, since the flexible material behaves differently feeding through a standard print mechanism than rigid filament does. Filled filaments (wood-fill, metal-fill, carbon-fiber-reinforced) add visual texture or specific mechanical properties but can be more abrasive on standard printer nozzles, sometimes requiring a hardened nozzle to avoid excessive wear over repeated use.
The one thing people forget
Check a specific filament brand and color against its actual diameter tolerance consistency, not just the nominal 1.75mm or 2.85mm size — filament with inconsistent diameter along its length can cause uneven extrusion and print defects that have nothing to do with printer settings or the correct temperature being used, and this quality difference varies more between filament brands than most buyers initially expect.