It's a charming little short-form series that's obviously based on a four-panel manga. I enjoyed it. It's definitely one of the better short-form anime.
The title means "The Landlord is in Puberty", which you might find worrying. Don't worry. It's innocuous. Maeda and Reiko's landlady is indeed a young schoolgirl (Chie) and they agree that she's cute, which admittedly in some manga would put you in fear of disturbing plot developments. The worst this show does, on the other hand, is to occasionally tease you with cross-genre awareness. Maeda and Reiko end up essentially being parental figures. Maeda has an office job and wears Dad glasses. Reiko has a figure, but dresses in baggy jumpers. Occasional episodes will do something that would in another genre (and without the age gap) have been a set-up for romance, but this is a harmless fluffy comedy and so the point of such scenes is merely to have some fun with Maeda and Reiko.
Maeda will occasionally be a bit silly or self-conscious, but he's basically normal. Reiko seems to see Chie as functionally adult in the first few episodes, which makes her a bit of a weirdo, but she calms down after that.
Chie's the most important character, actually. This is right and proper. We never learn much about Maeda beyond his life as Chie's tenants, although Reiko gives out a reasonable amount of maternal guidance. However we learn quite a lot about their landlady. She goes straight home without participating in after-school clubs, for instance, so she doesn't really have a social life. Maeda and Reiko vow to fix that. Reiko even succeeds, albeit in pyrrhic fashion by making Chie such a terrible-looking packed lunch that her failure becomes a school talking point and inspires Chie to found a cooking club.
There are some "learning a bit more about grown-up things" episodes. Reiko delivers a lecture on underwear and takes Chie and her friends shopping.
It's just nice. The cast are nice. The world of the show is nice. Chie always wearing school uniform is obviously a visual shorthand for the sake of easily communicating the jokes in a four-panel manga, but at least the show's making a character point of it. (Chie likes her uniform and explains in ep.2 why she even wears it on the weekends, but eventually starts wondering in ep.11 whether this might not be weird.) It's a shame it's so short, really, because it's so pleasant and relaxing that I'd have happily watched far more of it... but no, all we get is 24 minutes, including repeated opening titles. I'd still recommend it, though.