Update Drupal core from a low version I have to update a website from 7.14 to 7.31.

I feel like this contains a lot of risks. As anyone updated so many versions? What are your recommendations ?

I figured it would be better to update version per version instead of applying the 7.31 update right away.
I made sure the core was not modified.

Thanks,
As long as core is not modified in any way, there should be no risks of updating it straight from 7.14 to 7.31. It will apply all database updates from each version in between. There's literally no difference in doing it one version at a time compared to doing it straight to 7.31.

But as always, test it in a development environment before doing it in production and always make backups.