TL;DR: Is 1995 correctly written as MVM, or as something more like MCMLVL? MCMVC? MCMLXLV? MCMLXXXXV?
From what I recall from my Latin classes (European highschool...), you are not supposed to write more than 3 identical subsequent symbols. However, this rule hasn't been consistently followed in modern times from what I can tell by a little web research.
Perhaps it'd help if I knew how the Romans themselves wrote larger numerals... Would they write CLXL or CXC for 190? Something else still?