No poet is required to write in stanzas, or indeed in regular forms at all. Coleridge's 'Dejection: An Ode' has a rhyme scheme and sequence of long and short lines that goes without regular pattern, following the mood and whim of the poet. Such a form is known as an irregular ode.

A poem with grandly conceived and executed stanzas, such as one of Keats's odes, should be like an enfilade of rooms in a palace: one proceeds, with eager anticipation, from room to room.

The Italian word 'stanza' means 'a room', and a room is a good way to conceive of a stanza. A room, generally speaking, is sufficient for its own purposes, but it does not constitute a house. A stanza has the same sense of containment, without being complete or independent.

James Fenton Quotes