Most of the time is within XX miles, obviously if you are selling beeswax candles at a farmers market you don’t want a competitor there, but who cares if it’s the town over. If your selling nationally then it also doesn’t make sense because there’s more than enough buyers nation wide for many competitors.
I personally have never signed an exclusivity contract with a client, on the flip side it’s never been a conflict of interest either.
In face I have two of the same industry clients in different regions and they love that they get free info on what’s working from me having both of them. It splits their try something new cost in half