Re-tip or Replace?

I have a 40 year old Dynavector Ruby that still sounds great, but I think it will soon require a re-tip.  The question is, should I pay the $350 or so to retip it, or replace the cartridge with a comparably priced Ortofon, Audio-Technica or Nagaoka?  The system consists of a Luxman PD-277 turntable (another 40 year old piece), Schiit Mani phono preamp, Schiit Saga preamp, Rotel RB-980BX amp, and Martin Logan ESL speakers.

Thanks in advance for any advice.
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jnorris, replace it. The little wires inside that connect the coils to the pins are subject to fatigue and work hardening from years of vibration. They will eventually fail and then the cartridge is done. I would not spend money on a 40 year old cartridge for this reason. Have fun getting a new one! the Audio Technica AT ART9 and the Ortofon Quintet Black S are both great cartridges and great values. Both will work very well in your arm. 
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Re-tip or replace what? You will get more helpful responses if you use a specific subject. 
Buy a new cartridge. Replacing the diamond with a new one and a blob of glue will compromise performance! 
You can wait for a nice deal on ebay, i bought my rare DV 23RS MR (with Micro Ridge stylus) NOS from USA for about $450-500 one year ago. This is very close to what some people change just for a drop of glue and a new stylus tip. So i think you can buy a whole cartridge, even unused in the box.

Some other cartridges can be found too, but for $350 it will be hard to find anything close to DV23 Ruby, those new MM are not that good.

In my opinion it is much better to pay more for original cartridge than to mess up with retip.
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@mijostyn653:  Those cartridges are way out of my price range.  I mentioned comparably priced to $350.

@roberjerman: I was planning on using Soundsmith's service.  They show a Ruby Cantilever / Nude Contact Line Diamond for $350.  I don't know anyone that does a diamond with a blob of glue.

@chakster  It may be just me, but I don't trust ebay.  Too many counterfeits/scams/ripoffs.

@viridian I'd have to check on the cantilever length.  I'm assuming, perhaps naively, that what goes in matches what comes out.

And thank you all for your responses!

Yes, if you can get a nude diamond with a ruby cantilever! The price is reasonable.
I agree with chakster. Retip with ruby/stylus combo will cost +/-
$500 . For this price you can buy an NOS sample. Then this
cart has very short cantilever so the question is if retippers
can get those from their supplier. 

Excuse me. The way I read it was that you would spend 350 just on the retip and I did not think that applied to a new cartridge. The Dynavector went for $900. So I mentioned $900 cartridges. In $350 price range you should consider a Grado or hang on and save. 
The Grado is the polar opposite of the Dynavector.  Where the Ruby is open and airy with a wide, deep soundstage, the Grado's darkness and lack of high end extension presents a whole different perspective.  I'd be considering AT VM740 or Nagaoka MP-200, amongst others.
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It may be just me, but I don’t trust ebay. Too many counterfeits/scams/ripoffs.

Well, it’s absolutely impossible to rip you off on ebay when you pay with paypal, buyer always protected and full refund always guaranteed by paypal buyer’s protection.

There are no conterfit of old Dynavector cartridges, but i suppose you know what is Dynavector and you can recognize it, i had 4 different models, two NOS from ebay. I have returned one cartridge for full refund when i realized the cantilever is a bit off-centered, return shipping has been covered by paypal, so no loss at all.

If you prefer to buy cartridges from audiophiles on audiogon it is not a problem, but not as secure as on ebay with paypal.

The only scams I've ever been a victim of has been right here on Audiogon.  However and as chakster says, since I used PayPal I didn't lose a penny either time.
The only scams I've ever been a victim of has been right here on Audiogon.
That's interesting, because your Audiogon profile shows you've never bought or sold anything here.
I know, although I have no idea why. Might be due to the account being hacked a while ago, although that’s just a guess.

Whatever the cause, I fell for an Ortofon Cadenza Bronze last year. A good, but not too good, price, a seller with a fair amount of feedback and a PayPal option. Waited for the cartridge to arrive for a bit longer than usual, during which the seller kept up comms for a good while, and then his account was suddently locked due to having also scammed someone else.

Complaint sent to PayPal with reference to the closed account here and voilà, a refund arrived 3 days later.  Quite impressive really and much smoother than expected.