Hello Lisa
It isn't a requirement, but is considered good practice and there are very, very few authorities (I only know of one) which don't allow it. Practices vary slightly, but a common approach is up to 3 minutes per speaker, but if there are a lot, then some 'grouping' is encouraged. Time limits need to be firmly stuck to. And if, for eg, there is a speaker opposing an application (for 3 minutes) then there is an equivalent time allowed for the applicant (or supporter) to speak too.