Deep scratches on vinyl-bad for stylus?

The stylus is much, much harder than vinyl. Scratches will do it no harm.

Agree that deep scratches will not harm a stylus.
However, if the stylus hits a 'nick' that makes a loud noise, you might get worried: the diamond is just glued on that tip of the cantilever, and ripping it loose is hard to do, but it could come off if it hits something with enough force.
Normal scratches should cause no harm, but bits of hard materials embedded in the vinyle could damage a stylus.

Agree that it will not cause harm. As far as playability is concerned, you will find that different stylus shapes ride in different parts of the groove, either higher, or lower as it were. This means that a scratch may be sonically diminished or accentuated depending on the stylus shape and where the defect is in the groove. I have experienced this many times. If you have stylus related groove damage, rather than scratches from just being high or drunk, or operating your table shipboard, then you will find that the right cartridge will minimize this.

Ha, I just posted a similar question, not having seen this one in time (googled it didn't come up).

I'm glad to hear the comments above. I've recorded (to digital about a dozen or so old blues and rock records that have some serious scratches in them (a couple of which caused skips).

My stylus is rather new so if I can avoid replacing it (just stylus, not cartridge) that would be good.

The other problem with old records can be crud from previous owners that I can't seem to clean off. I guess if it doesn't come off with soap and water, it'll just translate to noise but (for just a few records) not harm the stylus or get stuck to it.

I have a small brush with Stanton liquid that somebody gave me, but I'm not sure how much it would help.

I don't think that there's any definitive study or proof, but I have a great deal of difficulty believing that playing vinyl with deep scratches and similar damage is not going to affect stylus and/or cartridge life.

Think about it for a minute. While we all probably do it from time to time, it's not going to be good for the stylus/suspension if done on a regular basis.

I can only speak of the Shure cartridge but a friend dropped the cherry of a joint on my Led Zeppelin One and burned a hole in it.When it was returned to me I didn't notice it and played it. The record was sounding fine and then the wierdest sound like sandpaper being dragged across wood as the record was being held in one spot by the cartrige and the platter was spinning underneath enveloped the room. Don't worry needles are pretty tuff. RIP Guy.