For the kind of programs I write for AVR-8 it seems insane to use the calling conventions of C, so if I write assembly I can sometimes keep the inner loop variables in registers (big register file) and otherwise use the methods he describes. I like “coloring” functions in an app like that, if I know a red and a green function will never be active at once I can reuse locals/parameters for them.
Yes, C's stack usage can be unintuitive when working in a constrained environment, especially when accustomed to the affordances of desktop operating system. I once joined a project where several developers had spent a couple weeks trying to track really hard to pin down bugs in several subsystems they were developing in a microcontroller codebase. They would move things around and the bugs would move. After tracing things a bit and setting a trap, I found the places in the codebase where the call stack got too deep and was scribbling over other data structures.
Putting a `out-of-stack? branch` check in every function prolog made an embedded chip programmed in C much nicer to work with. Cost a few instructions which was contentious but definitely a development aid.
