This post is inspired by the most recent episode of Tari Tari, and also by this post from July by SnippetTee about the architecture of Tari Tari. So there will be spoilers after this point.
Side Note on Character Ages
This post is primarily dealing with the perceived age of buildings. Obviously a similar post could be written for the apparent ages of female characters in anime, especially for everything between the ingénue and Driving Miss Daisy.  I did include it in an earlier version of this post, but it just wasn’t working.
To me the high school also looks, and feels, like a new building with a modern aesthetic.
Except for the slightly inconvenient fact that it was the current vice principal’s high school. The daughter of her eldest friend is one of the main characters, and will be graduating this year. See the opening credits below at about 1:15 for a sequence that confirms this:
This means that the building is at least 20 years old, and probably closer to 30.
This is a problem when, as it did in episode 11 Waxing and Waning, redeveloping the site becomes a major plot point (that would be the spoiler).
The last time I remember this sort of disconnect was when I saw the Ridley Scott Gladiator where the clean, shiny, perfect Rome also nearly shattered my disbelief.
However this is something that can be done right. The earlier PA Works title Hanasaku Iroha had a similar issue but the main building felt suitably old. The supreme example is probably Old Home in Haibane Renmei .
I do appreciate that the designers went to a lot of effort to get the school so pretty in Tari Tari, and it does look fantastic. However 30 years of high school kids is going to leave marks, marks that the building earned, and Tari Tari would be a richer viewing experience if they had been worked in.
 I don’t have the exact quote but I seem to recall a similar line to this from Goldie Hawn’s character in First Wives Club.