The router is wherever the cable came in
Usually a closet, a back corner, or under a desk behind a box of files. It was placed where the installer could reach, not where the office needed coverage. The far end of the floor has been on one bar since the day you moved in, and everyone has quietly worked around it.
The provider’s box is doing all four jobs
Modem, router, switch and Wi-Fi in one unit, aimed at a household. It is the single most common bottleneck in a small office, and it is rarely the thing anyone suspects. Separating the Wi-Fi out to a proper access point or two often fixes what looked like a slow internet connection.
Everything is on one flat network
Workstations, the printer, the guest phones, the security camera someone added, and a smart TV in the meeting room, all on the same network with the same access to each other. That is fine until it is not, and separating guest traffic from work traffic is a short job with a real payoff.
Nobody knows the passwords
The router admin password is on a sticker, or it is whatever the installer set, or the person who knew it left in 2021. This matters the first time you need to change something urgently. Getting it documented properly takes twenty minutes.