One healthy beep on startup is normal, any other beeps either on startup or while running is usually an alert that something is not quite right. From what you said so far it could be (and only could be) that your CPU is running hot probably due to a wornout/faulty fan.
If you can not fully explain your beeping occasions to ACtheTROLL's Qs, google for "COMPUTER BEEP CODES" and see if anything resembles what you are experiencing.
It is up to you but I wouldn't leave it like that.