In M'sia, normally people changed together with water pump cause don't want to pening2 later if water pumpr broke etc. Bare in mind that most of water pump here is doono what brand (aka cap ayam brand) and normally the lifespan is short.
As the water pump comes the original car (OEM), for example my previous lancer ck water would last until i sold my car, ie after 5 years using the car & about 167,000 kms milleages.(not considering the car been used in Japan before that).
My few months back timing belt change i don't change the water pump cause my opinion the original/OEM waters pump would last for around 5 years like that.
So, the chances for water pump broke down still 60-40 la. 60% ok, 40% not ok...but it's strongly adivice for you to change the pump since u can get the original 'original' part in Japan. FYI, here got so many fake 'original' parts(tipu punya)!!..happened to me when i wanted to change my timing belt last time.