Flying from RIC to IAD, the most popular and "efficient" route is BENTLY -> CAVLR3:
However, you could more simply depart north out of the RIC Class-D, intercept the BROOKE VOR on the edge of the DC SFRA, and then accept the inevitable vectors from Potomac Approach to IAD:
While the time en-route and distance are only trivially shorter, it still illustrates my point: choosing to fly a "non-standard" route is both quicker and potentially easier (without a GPS, hitting the intersections is a more complicated procedure than "direct to BROOKE VOR").
From my training I understand that these airways are primarily used to organize air traffic to reduce risk of collision in uncontrolled airspace as well as to improve flow and organization in controlled.
Which methods (routes/airways vs direct GPS/VOR/DME nav) are more commonly employed by IFR and (vs?) VFR pilots?