In this example, I take the business versus lifecoach. If you would have to make a decision between these two, I would go for [life coach new york] and even add [brooklyn] to it to beat the competition.

You see that if you add Brooklyn, it gives no searches per month but this only means that Google can not measure the amount.

It could be 5 searches per month. And even with 5 on the #1 , most of the times means almost certainly 5 clicks per month if you are on #1. And because a life coach does not need a big number like a webshop extra per month, 5 could be a good start. 

Furthermore you also automatically optimize for the less long keyword-set (without Brooklyn).

I would like to see your Keyword researches with a screenshot of the research and a little explanation if possible so we all learn from this.