Planter Size

If I want my plant to be about 3-4' tall upon harvesting how big of a container should I plan to mature them in?

I would say that 3 gal. container will be fine, right now I am using 5gal. buckets but , sometimes I wish I had done 3gallons for space saving

I think that some people will say five gal. because they say the foliage will only be as wide as the bucket or roots