How big should a recording booth be?

How big should a recording booth be?

A 5 by 6 vocal booth is fine for vocals and amps (even acoustic guitar) so going bigger ( like 9 feet ) may or may not get you any extra benefit, but if you are thinking of recording a drum kit, 6 by 9 would be better.

Do you need a vocal booth?

You don't technically need a vocal booth. Good alternative is something like a voxguard. Anything that could isolate the mic would be good if you're in a very untreated/reverb-y room. If you have a slightly decent room without lots of reflections, then you don't need anything other than placement!