Old NAS worries

I am running a NAS on my network that is now into its 13th year, both the 2-bay unit and the drives. They are WD 2TB red drives. I have never had an issue with this hardware, and every time I run diagnostics no problems are found. It is just a simple duplicate RAID config, so if one fails I will have the other. It is a Zyxel brand, and support was ended long ago for it. Most of what I hear and read I should expect to replace this system soon, and I have started saving for it. I recently upgraded my network to a 2.5gb switch and put 2.5 cards in my PCs with proper cabling for it, so in buying a new NAS 4-bay I plan to purchase one that has at least 2.5gb LAN ports. Wondering if anyone else has any NAS lifespan recommendations? Powercat in Texas