Vastly over-rated IMHO
since one field looks very similar to another after a while.
Anyway there is no red line on the ground to mark the edge of controlled airspace.
I only ever rouse from my slumbers (like IO540) inside the FAF or if I get an audible traffic proximity alert - one eye slightly cracked open is usually enough to have a quick scan around.
Otherwise I set max power cruise, set the alarm clock to go off 1 min before landing, kick my shoes off, lie back, let George do the flying and have nice nap.
ZZZZZZ ZZZZZZZZ ZZZZZ
SB