Just as manga characters change and evolve, anime characters do the same. Maybe it’s because artistic styles come in and out of fashion or due to the visions of different studios or directors. Whatever the reason, they change.
Twitter user Billy Morgan recently cataloged some of the years. The time that they cover varies. For example, the above GeGeGe no Kitaro comparison spans decades, while the Gintama images are separated only by a few years.
Other Twitter users replied with comparisons of their own.
Feel free to add any other character evolutions in the comments below.