Elevation and guidelines in haircutting

Three degree values and two kinds of guide account for most of the cutting domain. They combine predictably, so once you can name what each one does on its own, the scenario questions answer themselves.

0 degrees	A blunt, one-length cut
45 degrees	A stacked, wedge-shaped weight line
90 degrees	Uniform layers throughout
Above 90 degrees	More weight removed, longer layers
Stationary guide	Weight, or increasing length, as sections travel to one line
Traveling guide	Taken from the section just cut, so the guide moves with you
Design line	The line the whole cut is measured and built from
Tension	Must be even, or the line is uneven once the hair is released
Cross-checking	Re-parting in the opposite direction to check for evenness

Where the point is lost: One consultation question follows from all of this and is worth knowing separately: a client with fine hair who wants more apparent fullness is served by a blunt perimeter line, which keeps the ends looking dense. Layering removes weight, and on fine hair that reads as less hair rather than more movement.