From Seth's Blog:
It's okay to treat some customers differently, but first it pays to figure out who you're dealing with and why you want to re-allocate your resources.
I'd go as far to say it's impossible to treat all customers the same even if you wanted to. Customers who contact your customer service are getting 1-on-1 service that the others aren't.
Just be honest why you're treating customers differently. Because they had a problem, because they paid us the most, or because they are the loudest are all valid responses.
Eric Davis
Go beyond Average Order Value
Go beyond just Average Order Value and learn how your customers perform in various metrics.