The only numbers I will ever spell are one and zero, and only when using them as a pronoun, or for emphasis, respectively.
Is there ever a reason to not to use symbols when dealing with numbers? Why would "fourteen whatevers" ever be preferable to "14 whatevers". It's just so much easier to read numbers as symbols, not spelled out.
(Caveat, not including multipliers, like "273 billion").
I especially hate what we the Czechs do. We mostly read numbers the same (21 = twenty one), but then once every blue moon some dimwit says 21 like "one and twenty" like he's fucking German or something. German is bad enough, but why do we have to mix it???
Tho like I said before, it's not perfectly accurate. In Czech 90 + 2 is the official way, but many people around Prague and closer to Germany do in fact occasionally say 2 + 90.