I have the Rega Bias 2 and I was wondering after how many hours of play should I replace the needle?
Normally somewhere between 750 and 1000hrs I would say.
youll hear when you need to do it as the sound begins to blur slightly
We tend to find it's about 1,000 to 1,500 hours depending on localised conditions. Cleaning fluids also, generally, reduce the life of the cartridge.
Why do cleaning fluids reduce the life of the cartridge/stylus?
They're seldom as pure as suggested and start to corrode the cantilever, react with the suspension or reduce the effectiveness of the cement that holds the stylus in place.