Use different colored outlets to distinguish the multiple circuit
in a box - I used white and ivory. If you're running three circuits
along a particular wall, you can get brown, too. Mark the breakers
with the color they control ... and this lets you spread the
load across the various circuits around the shop, if you're running
close to the edge.
The little retractable cord reels are great stuff, by the way. I have
two of them hanging from the ceiling in various corners near doors,
and also one hidden under a bench ... in the cubby where I store the
shop vac. So the vac is plugged in and ready to go when I pull
it out - and is close to the most commonly vacuumed area (the
Air reels are good, too, if you get some that seal well enough
that you can put them up out of reach.