You can sometimes date Roman coins based on how much the bust looks like the bust of the previous ruler, as it would take a while for busts of a new ruler to be sent to all the mints. So initially they made them like the old guy but a little different.
On the other hand, the legends (lettering) on coins is always longer for new rulers - with all the titles and whatnot - and then later, once the population knows the guy, they are shortened again.
You can sometimes date Roman coins based on how much the bust looks like the bust of the previous ruler, as it would take a while for busts of a new ruler to be sent to all the mints. So initially they made them like the old guy but a little different.
On the other hand, the legends (lettering) on coins is always longer for new rulers - with all the titles and whatnot - and then later, once the population knows the guy, they are shortened again.