Hi Andrei, well it all depends on your own particular needs... it is pretty typical for hard surfaces to not animate by stretching or bending, they do tend to be animated by rigid body motion only and if that's the case then yes you're right.

But it could be possible for someone's particular project to need hard surfaces that bend and flex if they're going to try and make it move with some kind of personality or something like that... whether that applies to your specific project or not is something that only you can answer.

It's often better to base your requirements on what you are specifically trying to do. Ironclad abstract rules like "every polygon must be a quad" or the reverse don't really make sense, try to do what applies to your particular needs.

- Michael