Five counties, five auctions: what changes at the Davidson County line
A radius around downtown spends your money in places where the buyer, the courthouse and the competition are all different.
Draw geography around the places you actually serve and want to serve. Davidson, Williamson, Rutherford, Sumner and Wilson behave as separate markets, and a household in Brentwood arrives at a first meeting with different assets and different expectations than one in East Nashville.
Give each its own campaign, its own budget and its own reporting line. Averaging them together produces a metro number that flatters your strongest county and hides the one quietly eating budget.
Set location targeting to people in or regularly in your area, not people showing interest in it. Nashville is a destination name, and interest based targeting will happily sell you clicks from tourists and from other states.
Exclusions matter as much as inclusions. If you do not take matters filed two counties out, exclude them rather than paying to say no on the phone.