Cartridges

KISS

+ 1 to “both”

without high quality vinyl records you never will be able to discover high-end cart/TT and arm/phono/pre/amp/spkrs sound advantages!

IMO an ulrasonic cleaner makes a vast difference to new and old vinyl alike. If you have a lot of vinyl it is worth having one as it is amzing the difference it can make to the sound.

Agree with the view that the quality of the pressing makes a vast difference - I rely upon discgogs to find user reviews of all the various pressings and it helps you to find better pressings

Cartidge should be well matched to the arm and table (and system in general).

Separate issue from the records. I almost exclusively buy new, and the audiophile ones typically sound great (especially the 45s), although if the original tapes aren't good, the mastering can't correct for it.

Catchy title. OP could have put entire query in title.