Some components too old now?

Thanks for all your comments. Boiling it all down, it seems that the only thing I should consider is potentially changing my Aragon DAC.
Does anyone know much about the Aragon D2A? It has a separate power supply, and I remember that in its day it was considered one of the best.

Hmm. Thanks gdnrbob - really interesting.
Reading that thread, and over-summarising again, it seems as though a really good 90’s DAC (like the Aragon) will still sound as good as a decent modern one, but the difference is a modern one will have far more functionality. 
Is that the way you read it?

I’m using an optical connection between the CD and Aragon DAC. I must have discovered long ago that this gave me the best sound. Is USB any better...?

PS I don’t think I’ll ever use streaming or HDD so that’s not a consideration. I’m primarily vinyl, and CDs are so cheap these days second hand.

@gents In terms of replacing caps - I hear you, and that is one of the things that worries me. However, as I understand it that is more typically an issue with the power amp, not the preamp or CD player or DAC? (My power amps are only 6 years old so that’s not a concern).

Whilst I appreciate your advice @fsmithjack I personally far prefer going to my vinyl and CD shelves than turning on a computer or hard drive. Call me old fashioned. There’s something immensely pleasurable about simply handling those records and CDs that are associated with many personal memories. I could never get used to using a hard drive or streaming as it wouldn’t feel right. (I do listen to music on an iPhone when I travel on the train though!)
I’m also very comfortable with my other kit and those are the bits I have changed over the years. I think I’ve been through at least four turntables, three power amps and five pairs of speakers over the years - I only mentioned the old bits I hadn’t seen fit to change as I’ve been very happy with them.
I guess following all the advice, it’s the DAC that I’m now focusing on...

Ha! Nice one @danvignau 
I’m with you. The focus is on whether I should update my Aragon D2A DAC cos it’s 28 years old, and it’s the one digital component I have and so the one that should benefit most from an update. I’ve been a sucker for Aragon ever since I heard a 4004 power amp in 1990. Bought it and loved it for 27 years, and that lead me into the 24k pre-amp with phono stage (love my vinyl) and the D2A DAC to accompany the Marantz CD80 used as transport.
So far the jury is still out. The Aragon DAC has a separate power supply and is still very highly regarded it seems. Not sure I want to risk swapping it for a soul-less new box of silicon chips.

Good advice 4krow. I need to find someone to replace the caps on my Aragon pre-amp and power supply for the Aragon DAC - unless I learn how to do it myself. Will probably try to do it myself as my kit is far too heavy to go lugging around and I’m loathed to trust anyone else with it...