Cary 300SEI, when to have serviced?

[Breakdown7]

I have a Cary 300SEI from 2004, all original, never upgraded. When should I consider having the unit serviced? It still sounds great to my ears, but I can't help but wonder about the upgrade options available for these fine units, and also the effect of being played for the past 10 years.

It seems like Cary Audio charges quite a bit for the various upgrades. I have considered taking it to my local Cary dealer for a checkup in their full-range service/repair center, but just not sure. Just wanted to get the opinions of others here on the forum.