The reason why "it depends" is so often the answer is because legal questions are very situational and fact-specific. You'd need to consult with a lawyer on you

The reason why "it depends" is so often the answer is because legal questions are very situational and fact-specific. You'd need to consult with a lawyer on your specific situation to get an answer. But, generally speaking, a quick consult and having a lawyer write a response letter is a few hundred dollars. Let's ballpark it as $300-1000, depending on the nature of the case. Now, that's assuming that the company that sent you the C&D doesn't sue you. If they sue you and you go to court, the lawyer fees go up quite a bit and become pretty much impossible to ballpark (though I'm sure someone has tried). Having a lawyer on retainer isn't really necessary. It might be something you do if you're a business that doesn't have a lawyer on staff, but you want access to a lawyer's time when you need it. For most regular folks, I can't imagine setting up a retainer until you need to engage a lawyer for a case and want to guarantee their time.