Testing stylus wear.

What you're suggesting is a guess, not a test. That's because you're assuming that the new cartridge is undamaged and within spec.

Styli can certainly be assessed for wear using a microscope, but you need to know what you're looking for, which are "cat's eyes." Shure has an authoritative reference here.

I saw some of the Shure photos on the internet. It looks like it boils down to smooth tip surface for good styli and dented or non-smooth tip surface for worn. I’m not sure if I’ll be able to see the "cat’s eyes" but the smooth tip surface should be visible. I’m also curious about whether there is any difference in recordings made with both. In any case, if my old stylus looks good I’ll be happy to wait longer before starting to use the new one. I don’t plan to test the cartridge with a microscope. The styli are pretty easy to just pull out and push back in again.

If you really want to check the cart for wear, send it over to Steve at VAS for a checkup and cleaning. He has an excellent reputation and I believe he will give you an honest appraisal. 

It's easy to see the stylus wear planes develop and grow with a decent microscope. However, having the 'scope's illumination set correctly is critical. When that requirement is met, the wear planes light up like oval headlamps.

Update:

I got my new 2M Blue stylus from Fluance, even though I don't own their TT because most other outlets had the stylus on back order. They also gave me a $10 coupon which covered most of the tax (funny that a Canadian company has to collect tax for a state in the U.S.). I was surprised to receive not only the stylus I ordered, but a new cartridge too. I called them and asked what happened and it turned out it was a mistake. They said I could keep the cartridge (which I don't need anyway).

I also got the Jiusion microscope, thinking that I'd check the old stylus. It turned out to be a huge pain to focus on the stylus and enlarge it to a reasonable size, so I returned it to Amazon, where I bought it.

It might just be impressionistic, but the new stylus seems to be a slight bit more detailed than the old one. The best thing is that now I can stop wondering whether I have to change it for a long time.

You may want to get a stylus timer to keep track of your hours. All you have to do is remember to turn it on and then off when you are finished playing records. I bought mine from Music Direct.

Another resource:

I'm afraid your USB microscope will not do the trick. You need high magnification with a large depth of field and special lighting to see the wear. This is an expensive device, over $1000. The best way to do this is to take a picture of the stylus when new then a new one every year until you spot wear then replace it. The "cats eyes" refers to wear on spherical and elliptical styluses. With modern stylus profiles you will see squinting cat's eyes, more slit like. This is looking straight down on stylus. Traditionally I used a medical microscope with special lighting. The problem is a very low depth of field so you have to look at each view like you would a CT scan, one slice at a time. 

I am Wed to Ortofon Cart's, I am familiar with the Kontrapunkt b (Kb') and the Kb' having undergone various types of rebuild. I know the Vienna Cart' very well and have been getting familiarised with the Windfeld.

I have not heard the Cadenza Black in a system I am familiar with, I do own one as a donor model for a rebuild and have been demonstrated the Black at a few HiFi events I have visited, and fully recognise the Ortofon family sound traits.

As for testing a Cart' condition, I usually use a professional assessment, but occasionally I detract from this method and something different occurs.

Not too many years ago a friend had purchased a Kb' with supposedly a few hundred hours of usage, my friend was not too impressed and thought the Cart's was with a fault or had been used much more than advertised. 

An arrangement was made between the friend and myself to comparing Two Identical Brand Cart's being the Ortofon Kontrapunk B, one owned by myself and the other the recent purchase the friend had made, each of these were believed to have less than 300 Hours of usage.

A Third Cart' was also used, which is a rebuilt K'b.

Two Tonearms with detachable Headshells were set up on a Plinth that has a well thought out servicing and mounting for a GL 75 (Saucepan Chassis Modification ) 

The Tonearms used was SME 3009 that has been serviced and said to be a very good sample, the other Tonearm is the Model I use today.

The friends Cart' when used on the 3009 was not very attractive, and not able to produce a SQ that could be considered as having the strengths of the Kb'. Both K'bs were used on the 3009 to verify if the condition was present with both, and the almost identical unattractive SQ was present from both.

The 3009 was no longer used and the Pivot Bearing Design Tonearm I own and use, was put to use, where the outcome was the SQ immediately improved and the replay was noticeably a very attractive presentation, and much in keeping with the strengths of a Kb..

The friend was satisfied with the condition of their Kb' and commenced the process of considering changing the 3009 Tonearm, in the end they ordered a Tonearm the same as my model.

Note: this assessment was only about helping a friend evaluate a Cart's condition as a comparison to another identical model, with similar usage history. Both Cart' owners were satisfied there was a good presentation from each Cart' probably indistinguishable from each other in the environment and equipment used. 

More recently, less than a week ago, another Kb' encounter took place, the following is a email sent following my experience, to the Kb' and system owner the demonstration was carried out on.   

________________________________________________________________

Hi A'
        Just a recap on our very interesting experiments and the discussions had at my much enjoyed visit yesterday.
Firstly the Kontrapunkt b (Kb) that was recently purchased as donor model with approx 1000 hrs usage, that was said to be lifeless by the vendor, was proven to be a Lazarus Kb', the Cart' in use with the latest guise for the design of the Tonearm certainly was a intervention that breathed new life into it.

There have been a few changes since my last visit and the use of the PC Triple C Wire as internal Tonearm Wire has stood out as exceptional choice, the latest mechanical work undertaken and now this electrical work as a combination has taken the Tonearm to unimaginable levels of performance.  

I do believe the new works carried out on the Tonearm and the introduction of the Low Mass Low Eddy Chassis Sockets to the New Design Phonostage, along with Cables using Low Mass Low Eddy RCA Plugs, are proving to be quite beneficial and the effect of these in use can be perceived as betterment .

The changes of the Cables with Low Eddy RCA's and without, showed that there are changes that can occur and some of these perceived changes are noticeably more attractive than another.

I was very impressed with the New Phonostage, where it is at now, in its almost final guise, it worked very well with the PC Triple C Power Cable when introduced, but the PC Triple C Power Cable in use with the Low Mass WBT RCA PC Triple C Cables was quite attractive and a first time experience for myself, where I could clearly identify a shape/envelope of a forming of vocal and note.

The exchange of the DIY WBT RCA Cable and introducing the use of the SAEC SL-5000 Cable took this perception of the shaping of a note further, the brush on the cymbal of the 'Why Worry'  track, took on a additional shape and the brush could almost be visualised in use, again a first for myself, feeling the presence in the mix is common to me, feeling the shaping of the bristles on the brush when producing a scrape/ Splash, that is new to myself and is extremely attractive when perceived during a replay.

The fact that we were both quite impressed and chose to keep the Kb' as the sole Cart' used during the session, not opting for my rebuilt Kb' or the Windfeld, speaks in droves.

I certainly have little recollection of the Kb' sounding so impressive,
could this mean that, 'Maybe and Just Maybe' the Kb finds its second wind while approaching a 1000 hours of usage?, but I do believe the most likely reason for the very good impression made is due to what it was mounted on and the ancillaries used to supported it throughout the presentation.

The work undertaken on the TTS Bearing Housing has been very pleasing and impressive, I look forward to the next stages of modifications.

_________________________________________________________________

If I were to go all out and use recollection as a judge of Three Kb's used in demonstrations over approx 3 years, I will say the most indelible for the very good impression made is the one reported to have approx 1000 hrs of usage and being lifeless, as made known by the vendor. Something is incorrect somewhere about the Cart's function, which my suspicion is that the vendor had not mounted it as a set up that let it excel, and was of the opinion the Cart' was in poor condition after the usage it had received.

Dear @rff000  : Even if you own all the hardware need it to make a stylus tip inspection you reallycan't to determine if that stylus tip is making damage to the LP grooves during play.

The @chayro  advise is the best one . 

Regards and enjoy the MUSIC NOT DISTORTIONS,

R.

Many of us have this issue. Thanks for bringing it up. The easiest way is exactly the way you describe. Have a spare new replacement stylus, and when you feel that it's worn, swop and listen. If it sounds similar, swop back and store the new. If it sounds like it's time to change, then change and get a new one for reference as the control. I do exactly that.