Do I need a lawyer if the insurance adjuster is friendly and cooperative?

A: Yes.  A lawyer represents you.  An insurance adjuster represents the insurance company.  Insurance adjusters want to settle your claim cheaply.  The sole purpose of the adjuster is to pay you as little as possible, as fast as possible, before you know the full nature and extent of your personal injuries.  A good adjuster will be pleasant and will try to make you comfortable so you will not recognize the need for a lawyer until it is too late.  Insurance adjusters are skilled in getting accident victims to settle their claims for far less than they are worth and in some cases may even trick victims who do not have lawyers into saying or doing the wrong thing for their case.