This is a good reminder. IME there are rarely announcements of any kind at the SCs (esp the larger/busier ones), so if a flight has been delayed you really have to stay on top of the monitor or the website/app because the departure time can change very quickly if, for example, a delayed incoming aircraft gets in sooner than expected and they can do a quick turn. Here, the OP said there was no notification except announcements at the gate, which is why I will also sometimes leave the SC to see what is actually happening at the gate (esp if I'm on the last or only flight of the day) -- you can always go back in later if necessary, but occasionally I've found myself running the last few hundred feet because all of a sudden I could see people boarding despite what the monitor was currently showing. Better to be safe...