If you find yourself asking this question, the answer is that Yes, you do need a lawyer (even if it is to tell you that you don't need a lawyer). Let me explain.
Lawyers are not the second oldest profession for nothing. People (and businesses) need them, and have from the earliest days. They can help, a lot. An old lawyer friend once told me, People can do their own dentistry work too, but having a professional do it is much less painful.
Ever notice when a lawyer, or politician, or judge, or police officer etc. is charged with a crime, or involved in a lawsuit, they most always have a lawyer helping them? Surely if lawyers were not necessary these "insiders" would not bother with them.
Criminal matters these days - even relatively minor ones - are fraught with risks and dire long-lasting consequences. Check out the pages and pages of the latest punishments for drinking and driving offenses for example. Civil judgments can haunt your whole lifetime. All kinds of regulatory agencies are out there overseeing business and professional activity too.
The fact that lawyers may be a necessary evil makes them no less necessary. Play it smart; play it safe. Call a lawyer first.