What's that saying... sometimes you've got to spend money to make money.
Seriously: a ScanGauge will pay for itself many times over if you're motivated to refine your techniques. And you could easily re-sell it after a couple of months and probably get most of your money back.
Of course you don't
need one to improve your skills, but the value of instant feedback can't be understated.
EDIT: if you do get one, don't use the group buy. Someone posted a link for Canadian orders in the Instrumentation forum.