It would not be a bad idea to think about what you would do if for example the police arrest you for some crime (it doesn't matter whether you did it), or if you are interrogated by government attorneys or police. If you are arrested, you will be given the opportunity to call an attorney. You do not give testimony when police ask you questions, you give testimony in court. This is a widely-known video explaining why you should never talk to the police, and you should watch that video (he recently wrote a book on the topic, You Have the Right to Remain Innocent). Then go into any interactions with the police apprised of the risks.
Suppose you witness a robbery and the perps escape in a car: the police ask if you saw them, and where they went. You should not lie, because that is a crime. It would be good to help the police in this situation: is there any risk to you? Do they think maybe that you are involved in the crime? I think the relevant distinction is between being asked information questions, and being interrogated. If you are being interrogated, lawyer up. Even if you are free to go, they may still be interrogating you, and you may not know that when you are not being detained, you have to explicitly invoke your right to silence if they casually imply that you've committed a crime (this is the adoptive admissions thing, not widely known by non-law people).
The reason why many people advocate lawyering up is that the risks arising from not getting competent advice are high. I think that video is a useful corrective to the thinking "I didn't do anything wrong, I have nothing to hide". It's not just drumming up business.