Other than the obvious if they are bent or damaged.. are rotors a replacable item like on a car?

Mine have heat marks and scores from various bits of crap… I ain’t in a rush to get new ones but they are over 3 years old ?

yes, eventually from wear. Manufacturer publish minimum thicknesses. Indeed the new Icetech rotors from Shimano have built in wear indicator.

Unless they have worn thin, leave them be 🙂 My XT 160mm are on 5 years of commuting and off-road use in all conditions, and have a lip because they are that thin…

My rear Avid 203 rotor that I use in the Alps has worn from 1.8mm to 0.79mm. Not good. So I have changed it. I get through front rotors at a rate of about once every two years. I’m a big biffer though, riding gritty Brecon Beacons trails.

yep in theory, although bear in mind that you haven’t got power assisted hydraulics applying very hard, abrasive pads to discs holding back a tonne and a half of metal like in the car!

I would hazard that unless they’re really thin i.e. in danger of developing stress cracks or your calipers won’t adjust far enough in (unlikely seeing as you can make the pads touch with most brakes) you would only see the benefit of new discs if your old ones were contaminated.

Superstar’s rock hard sintered pads seem to have worn a step into my front one. Not changing it for a while yet tho 🙂