Twenty explainers on the topics where a decision has a measurable consequence — in money, in hours, or in whether the part survives its job.
These are the longer pieces. Where a quick answer gives you a figure, a guide explains the mechanism behind it, so that when your situation differs from the example you can work out the answer rather than look for a closer example.
What is covered
The cost group covers the electricity method in full, what a failed print genuinely costs, spool weights and why the empty reel matters, and how to price parts for sale without quietly losing money on every job.
The settings group covers layer height against strength, wall count against infill, nozzle size, print speed and what actually limits it, supports, and the slicer profile settings that change cost rather than appearance.
The material-behaviour group covers shrinkage and tolerance, designing fits for printed parts, annealing, what moisture does to a polymer, how to store filament so it stays printable, drying, bed adhesion surface by surface, enclosures, and getting a repeatable first layer.
The one thing worth reading first
If you are here because a number surprised you, read the electricity cost method. It is the input people most often leave out entirely, and also the one most often overstated by a factor of five when they do include it, because a printer's power-supply rating gets quoted as its consumption.
Both errors are common, they point in opposite directions, and either one is enough to make a cost estimate useless.
How these relate to the calculators
Each calculator does the arithmetic. The guides explain where the inputs come from and how much to trust them. If a calculator gives you a result you do not believe, the corresponding guide is where the assumption you disagree with is written down and justified — and if it is not justified well enough, that is a fair reason to override it.
How long each one is, and why
These pages are long because the subjects genuinely are. Shrinkage cannot be explained honestly in a sentence, because the number depends on the material, the axis, the part geometry and the chamber temperature, and a single figure that ignores all four is the reason people compensate in the wrong direction.
Where a subject really is simple, it is a quick answer instead. Nothing here is padded to look substantial; the guides exist because the short version would be misleading.
Reading them against your own machine
Every guide states the conditions its statements hold under. Print speed limits assume a mainstream hotend rather than a high-flow one; bed adhesion advice assumes a modern textured or smooth PEI plate rather than glass; enclosure advice assumes a passive enclosure unless it says otherwise.
Those assumptions are written down so you can notice when yours differ, which is the point at which a general guide stops applying and your own test print starts being the better source.