If I have a concert and it's fancy and I wear a suit and stuff. Should I get a haircut?
If you think you need a haircut and have a barber or stylist who cuts your hair so it fully suits after being cut and not after a certain grow out period, then get a haircut.
If you can't groom it so that it looks good then yes you should get a hair cut.
If you have longer hair and it's long enough to tie up then just tie it back off your face.