When should I change brake fluid

[Niall]

Fluid will get darker the older it gets. New, its clear and has a slight straw colour to it. When it gets old, it will start to look like that morning after a heavy night piss. Thats when it needs changing. Just grab a few litres from halfords and bleed from the furthest to the closest to the MC. You want to keep bleeding until the fluid coming out is the same colour as the new fluid then move onto the next calliper and so on.

Id just do it anyway. You will be surprised at the difference it will make!