Cartridges

The answer to the OP's question is yes.  Do both.  You will get instant appreciation of your existing collection, but new records will probably sound better.  

In my humble opinion, buy 3 or 4 NM copies of an LP at about $30 each, chances are one of them is a so-called “hot stamper” and you’ve saved yourself hundreds to a thousand or two dollars.

If you properly cared for your records over the last half century, you don’t have this problem, of course. Original presses tend to sound best.

My two sense.

Having said that, I otherwise more or less agree with @bpoletti  

theaudioatticvinylsundays.com

Cleaning, especially ultra-sonic cleaning, is a very good use of money. With my US set-up, I get an improvement about equal to upgrading a major component. In addition, a photomicrograph at 1000 hours showed minimal wear of my stylus - instead of half worn out - so the US set-up  has already paid for itself.

YMMV

OP,

I highly recommend traveling to listen to some different systems. Shows can be good… but so few of the systems are at all optimal and so much to see it is distracting. I would plan a trip for a weekend… bring wife. Schedule a couple hours at two or three different audio stores. I would not be surprised if tubes still sound better. Listen to some pure systems to gat a feeling for the “house sound” (sound of a company’s products) you like. Try Audio Research, Pass, and a couple more. 

KISS