I disagree completely, unfortunately from experience. The need for lawyers has nothing to do with how much you trust the person-- the key factor is the amount

I disagree completely, unfortunately from experience. The need for lawyers has nothing to do with how much you trust the person-- the key factor is the amount of money, and your willingness to walk away from it. If the sum of money involved (now, or in the future) is large enough that you don't want to be able to get screwed out of it, lawyer up. The people you trust today might just turn out to be untrustworthy somewhere down the line-- you never know.