Filament choices: ABS or PLA?
ABS melts at a higher temperature, which means your machine has to run hotter in order to print with it. It also has worse adherence qualities, so many printers that print ABS have a heated bed to help the material to stick. PLA, by contrast, cools quicker and sticks better, and so you can generally print faster with it. If you’re making a part that’s to be used in a hot environment, such as the wheel on a dishwasher tray or a printer fan housing, you may want to use ABS to minimise the chance of it deforming in high temperatures.
There are also differences in how you finish your prints. ABS is soluble in acetone, which means you can wipe it over with the stuff to smooth out any bumps or blemishes. Acetone has no effect on PLA, but generally speaking PLA produces smoother prints to start with.
Some printers will only work with either one or the other, so check before you experiment.