Developing a feel for the difference
A practical way to actually develop a feel for what effort level changes is deliberately running the same kind of ambiguous request at two different levels on separate occasions and comparing what tCode noticed along the way.
Specifically worth watching for: whether it checked for an existing test before writing a new one, whether it considered more than one plausible cause for a bug before committing to the first one it found.
The difference is usually visible in the choices actually made during the turn, not in anything printed differently on screen, which is why comparing outcomes side by side teaches more than reading a description of the difference would.
Using the same exact prompt on both attempts, rather than two similar-but-different ones, is what makes the comparison meaningful; any difference in wording between the two runs makes it much harder to attribute a different outcome specifically to the effort level rather than to the prompt itself.
This kind of side-by-side comparison is most informative on a task genuinely ambiguous enough that a difference could plausibly show up, a clear-cut mechanical task will often look identical at every level simply because there was little room for the extra deliberation to matter.