Water Pump Should I change the Housing?

I need to change my water pump. Noticed it was leaking, I was having a look online and I found https://www.onlineautoparts.com.au/products/ZPN-16691 however you can also get it without the housing? What is the norm when doing the pump do you usually change the housing?

Most change both the pump and housing at the same time. Pump might be fine and may be your housing that's leaking.

Thanks I will get the pump and housing. Better to be safe than sorry.