My reluctance isn't that this isn't doable, but the amount of effort it would take to inspect every external surface for small gaps. Cracks, for reasons of personal head cannon, seem much easier to identify. Both the attic and crawl space require a fair amount of persistence in tight, dark spaces with not the best of footing and air quality conditions that are tolerable in limit situations without mitigating equipment.

The roof is also another tricky spot. Definitely worth it for critter sized openings, but I'm not sure I can pull it off for bug sized.

With that said, I think most people will get a lot of bang for the time if they inspect doors, windows and search for cracks on the sidewalk along the foundation.