If one is considering taking on a Breeding Bird Survey route for the first time, I will chime in to say I highly recommend it. Surveying a route is challenging and fun. You will learn new calls and sounds (I second Hugh's comments that birding by ear is a great portion of the bird detections, so some skills here are needed). Picking a BBS route will often take you to a new area, which you will come to know over the years and it will become a part of your birding knowledge and experience. It is great fun proceeding through the route and visiting its different habitats, with an idea from prior years of what to expect and listen for, but anticipating that there is always something new or different along the route from one year to the next. Many routes take you to beautiful places. Some thoughts on one route offer an example.
One of the routes I run in Colorado (since 2014) is named Powderhorn, located in Gunnison County. It begins at its north end on sage slopes overlooking Blue Mesa Reservoir and the Dillon Pinnacles. The route begins at 5:15 am, and the pre-sunrise light and clouds at the route's beginning are so lovely. Poorwill, nighthawk, Dusky Fly, Green-tailed Towhee, Sage Thrasher, Brewer's Sparrow, Vesper Sparrow....The next few stops have some small trees and oak shrubs that add a few different species. Next come many stops in wide open sage habitat, with stellar views off to the peaks of the San Juans. This stretch has produced Gunnison Sage Grouse nearly every year I have run the route. The overlapping songs of Sage Thrashers blend with Brewer's, Vesper and Green-tailed into a tangled web that I get to resolve at stop after stop. There are often Elk along here, spying on me. Just past halfway, the route enters a forest of Ponderosa pine and Douglas-fir, with aspen in not-too-recent burned areas, still with purple clouds of lupine. Grace's Warbler is regular here. Red Crossbill, wood-pewee, Plumbeous V, all three Nuts, Hairy, siskin, Cassin's, Mountain and Western Bluebirds, and more. From here the route heads up the lovely valley of Cebolla Creek, past the historic location of Powderhorn, and up along the flat valley bottom of partially flooded pasture (snipe, ducks, Savannah Sparrows, Sora, sometimes cranes) with a nice riparian corridor (Warbling V, Yellow Warb, Cordilleran, Broad-tailed, Lincoln's). The route ends as the blue spruce replace the cottonwoods along the creek, with steep rocky slopes of Douglas-fir flanking. Cebolla Creek is rushing here, and there are not too many bird voices amid the roar of the creek (Hermit Thrush and Hammond's Fly, Steller's). But American Dipper is there to look forward to at the last stops, as the route ends just north of the Hinsdale County line.
In going out to survey the route I always bird otherwise in the region, and so the need to visit for the BBS has helped me to learn alot about birds and birding in Gunnison Co, and I've taken advantage of being in the neighborhood to explore the wilds of Hinsdale County and other areas I would maybe not have gone to otherwise,.
All this is not to focus at all on the skill-building and skill-sharpening challenge of listening and looking, hearing and counting, all in just three minutes at one stop, then moving on to the next, repeat. And not to mention the trends or changes in bird numbers or species, that become evident in even just a few years of surveying. There is a commitment, that is for sure, but the fruits are many.