I was thinking about this and I wonder, how good are your records of old jobs? These days with computer storage as cheap as it is, you might be able to claim a value added service for repeat customers because you can still come up with details of their old jobs with you. Things like good diagrams of what you did, things you had to explore/document and even pictures for things like buried circuits and such before you backfill. If you have good sight lines in a photo, referencing things that are unlikely to change, you can get very close to a buried line without ever turning a blade of grass.
Some other guy bidding your job is immediately at a disadvantage. Most customers would have lost this information, even if you gave it to them.
