Frankly, I'm shocked that the advice of a lawyer would be to never talk to the cops without a lawyer.
It's just as extreme/stupid to say "never talk to the cops" as it is to say "always cooperate with the cops if you've got nothing to hide".
Obviously this is so situational that without knowing the specifics of each case it's nearly impossible to give any type of one size fits all advice. In general, though, I think responding when you aren't the target of the questions OR when what you are being questioned about is extremely minor (a traffic stop when you know the only thing you are guilty of is speeding or failure to stop or something like that) is probably +EV. The more serious the offense being investigated, the more likely you should be to have a lawyer, whether you are guilty or not, just to protect your rights.
It was a military situation, but I absolutely requested to speak with JAG when my CO tried to charge me with a crime (intentionally defrauding the US government with my eye surgery) that I hadn't committed. I also freely answered questions until that right was invoked, but once they tried to get me to sign anything or make an official statement, I refused and stood my ground.
I think most people with a normal level of common sense will be able to tell when it's okay to talk and when they should shut up IF they are knowledgable about their rights in the first place. That last caveat is why a lot of "never talk to the cops" stuff gets started - so many Americans are ridiculously ignorant of their rights and obligations when it comes to criminal investigations.