The title of this tip is a direct quote from Les Barker upon his seeing the title of the previous tip. There may be no such thing as a perfect poem. The art of writing is an
exercise in trading off between form, message, beauty of language, and the time available for creation. A poem may not scan perfectly, but the world wont end because of it.
In fact, going back to one of Peter Berrymans tips, getting it wrong is often what art is about. Michelangelos Davids eyes are astigmatic. It makes the statue seem more real. Having
the scansion perfect also means that you have created a poem with monotonous rhythm. Changing off in a few places is a good thing.