How many duds do you have to go through to get a keeper SP / MP?

[Mr. Spock]

I have to visit 3 or 4 MPs before I get one good enough to do a return visit, defining a keeper as a MP or SP you would go back to at least 3 or 4 times in 12 months. What is your ratio of duds to keepers?

 

[HG Hunter]

In my experience, I've rarely had a true dud. There have been a few, but very few.
My problem is trying to narrow down the ones I would repeat with to a manageable (read affordable) number.
There are so many who sound great that I haven't yet met and so many who have pleased me tremendously - who's next is often the dilemma.