At What Point is the Needle Damaging Records?


I have used my Denon 110 between 1-5 hours a day for the past three and a half years, and lately I noticed the highs are beginning to sound a little muted. Could I damage my records by not replacing the cartridge right away?
jmoog08
According to Neil Young, he's seen the needle and the damage done, a little part of it in everyone. :-)

I would replace or retip it.
Ballpark is 1000 hours I believe. Your way over that average. It probably will be different with every setup. Tracking distortion happens in a lot of cases. Sometimes, it will show up more in the inner most track. It has been said if you have damaged grooves from one shape of stylus, using a different type of stylus shape may still sound ok as it will ride higher or lower that the damaged part of the grooves.
I thought a typical stylus lasts about 2000 hours and it usually outlasts the suspension. Is this not the case?
I thought a typical stylus lasts about 2000 hours and it usually outlasts the suspension. Is this not case?

I could be wrong as I'm going by long term memory. I looked around the net, and Shure says about 1000 hours, and people were saying 500 hours or more on VinylEngine. I think some times they used to have timers that went to 999 hours from what I can remember. They're aren't all the dealers like we had in the vinyl only days, that used to have a good microscope to check to see how it actually was worn. I wonder were those good microscopes went? They might be in storage somewhere being wasted, or in someones collections that knew better than myself. Links to what I found.
http://www.vinylengine.com/turntable_forum/viewtopic.php?t=24807
http://shure.custhelp.com/app/answers/detail/a_id/4135/~/stylus-wear-and-record-wear