My own personal experience is that, in linear algebra, there are a lot of different ways to prove the same thing. When you search for a proof of something, you may find a proof that is overly basic and verbose, or a proof that is overly advanced and terse.

Finding an explanation of a linear algebra concept that strikes the right balance can be time-consuming or difficult. This is why you see, for example, a hojillion different articles explaining what quaternions are. Everybody is most comfortable at a different place on the complexity spectrum—from “a vector is (x,y,z), here are rules for how that works” to “a vector space is an abelian group V, field F, and a map in Hom(F,End(V))”.