Michael
I Love YTtalk
Intros and outros arent necessary but can be good ways of branding your videos. If you do decide to make one keep it under 10 seconds, under 5 seconds if you can so it is as short as possible and try having it after around 10-15 seconds of the video playing so you can grab the viewers attention right from them hitting play and then have the intro play briefly. I will have a two second intro when I start my personal channel.