YES. More good cases are lost because people think things like: "I am in the right", "Everyone knows he did it", "I have witnesses". None of these things matter if you don't know how to get them in front of the Court, Judge, or Jury. Almost all Courts hold you to the same standard of knowledge of the laws and the rules as professional attorneys. This means that being right doesn't really matter if no one can hear your evidence. This means even though everyone else knows he did it, you may not be able to tell the judge what everyone knows. And lastly, this means that even with witnesses you have to know how to have them properly found, noticed, served, subpoenaed, and professed to the opposing counsel in the proper time as required by law.
It doesn't matter if it is criminal, civil, family, contract, whatever, the rules apply. Unless you are in a small claims or JP court, you need an attorney, Even then you have the advantage if you have an attorney. The old adage I use around my office when asked this question is "You can be the smartest, wisest, well known, good looking, and well read person in the world, but when going to Court without a lawyer you are the equivalent of the smartest, wisest, well known, good looking, and well read Roman slave or criminal in the ancient Coliseum where you are basically naked and unarmed and everyone else is either a wild animal or a well armored and well armed Gladiator." You have the same chances of survival in both situations.
I hope this short article brought the point home. Good luck and God Bless America.