For me, janitorial falls into one of the most highly volatile and demanding industries. Low paid, low skilled, transient labor model who operates with relative autonomy and little supervision. It can be a nightmare for the owner at smaller organizational size with limited resources. The only way to insulate yourself would be at scale but it doesn't reduce the dynamic. It just shields you from it. Operationally it falls into the same or similar dynamic of a restaurant which is one of the hardest and most demanding operating models. I usually advise to avoid but at scale it is more viable.

Also, just to be clear, commercial vs. residential is a big factor. It seems like a lot of commercial office cleaning is done in the evening/overnights, so I would definitely consider that. I haven't run a janitorial company, but I have run a motel, which is somewhat similar in low wage labor. It can be hard to retain lower wage workers and the evening/night hours would make that even harder. I would also caution that even with commercial--those contracts can change. We just negotiated a 50% discount based on two other estimates for the cleaning at the office where I work. They were overpriced, obviously...but there is not much of a moat. Googling janitorial services came up with many options.