Should you always dress conservatively for a job interview or for some jobs should you dress as you would for a typical day at work?

I would suggest going into the interview with the mohawk down and dress a bit nicer than you would for a typical work day. I woudln't suggest going in there in a suit and tie, but you should dress nice. You are trying to make a positive immpression. You are more likely to "lose points" for dressing "punk" and having your mohawk up than for dressing a bit nicer than normal. It's just interview rules. Good luck!