I don't think there's ever going to be a time where this series doesn't manage to hold up.
I love series that show the lives of retail workers that shows what we, the customers, don't usually see. This series manages to have such an eccentric aesthetic down pat, and tell a humorous story with it.
Everything from the moments with foreigners who stop into the shop (see the iconic "SPECIAL YAOI BOOK" instance), to the designs of the characters (come on, who thinks of a different way to hide every employee's face and make them work with the characters themselves?), to the intro and ending (painfully chaotic and colorful, and sets a great tone for the show), all harmonize and manage to showcase the life of a bookstore worker. It's tons of things you'd never think would work together, but they manage to in the most bizarre of ways.
I've rewatched this show far more times than I'm willing to admit, but only because I don't think there will ever be another show quite like this. On top of that, it's so much easier for a busy person like me to watch this show, seeing that the episodes are all around 11 minutes long.
Overall, I'm truly disappointed that this show doesn't have as much attention as it should. It's a quick, fun show, and gives a nice introduction into the wacky world of a bookseller that just so happens to be a skeleton.