Cause its worn out and knackered and you need a new one?

What kind of bottom bracket is it?

give it a clean before going out and buying a new one.

my bikes making canary noises on the front disc brake rubbing. really annoying

Is it creaking or squealing?

If it's a creaking sound it's likely to be some dirt/mud between the BB and the frame. So a nice and meticulous clean will get ride of it.

In my experience BBs die from a siletn death, so check the BB for play. Which kind of BB is it? If it's an ISIS you might be able to get some new bearings. If it's HT2/Xtype you can open them, get some new ceramic bearing inside and regrease them.

Hope it helps.