Had my Western Digital My Cloud since 2015.

I’ve had my Synology DS215 for almost ten years. I’ve recently thought about replacing it, but I don’t really see the benefit. I’ll just replace the drives some time.

I built my 10ish TB (usable after raidz2) system in 2015. I did some drive swaps but I think it might have actually been a shoddy power cable that was the problem and the disks may have been fine.

I’d be more concerned about the longevity of the drives than any NAS itself. I moved from commercial NAS appliances to a self-built one. It turns out that they cost about the same (depending on the hardware configuration you end up choosing, evidently), but are MUCH better performance-wise.

The NAS will most likely outlive the software support and by far the HDDs you are putting in them.

Your NAS will last as long as your storage medium.

HDD lasts 5-10 years, SSD lasts like 10+

I had my DS213+ for a bit over 10 years, with no failures of any kind, just a bit of drive swapping for more storage space. Finally upgraded last year to a 4-bay with better performance and Docker support, but I would have kept using it otherwise.

Both DS220+ and DS224+ has been a pleasure to setup, but I wouldn’t replace your DS218+ just because. Just make sure your RAID is healthy and your backup too.

An alternative to a standalone NAS is to setup your own little ITX server. Only if you enjoy tinkering though, Synology is definitely easier.
At home I’m currently running Server/NAS/Gaming PC all in one.
It’s a Debian 12 KVM/QEMU host with an m.2 NVME disk for host OS + VM OS and 2x16TB Seagate Exos disks in RAID1 for data storage. The other hardware is a B650 ITX Motherboard, AMD Ryzen 7600 CPU, 2x32GB DDR5 RAM and AMD Radeon 6650 XT, Seasonic FOCUS PX 750W PSU.
With my KVM/QEMU host, Game Server and Jellyfin Server online it eats about 60W-65W, so not that bad.
The GPU and an USB Controller is passed through with VFIO to a virtual Fedora that I use as a desktop and gaming client.
Just make sure to have a sound dampening pc case so you can keep the servers online without being bothered. The GPU goes silent when the gaming VM is off.

I had a Helios that literally just started having trouble powering SATA disks a few days ago. I got it in 2019 I think, so only 5 years of life.

I use Linux LVM and either ext4 (for older volumes) or btrfs (for newer volumes, because I want the checksums across the data) so in principle I could throw the disks in a PC as a temporary solution.

I have put the disks in SATA to USB 2.0 caddies, and the Helios 4 kind of still works, but I’m ordering a couple of Orange Pi 5 and with USB 3.0 disk enclosures to replace it. It was kind of time anyway, since Nextcloud has dropped support for 32-bit CPU.

At least 5 minutes.

Using unraid is nice because you can keep replacing drives with lawyer ones as you need, or adding new drives to the array. It’s very flexible that way, despite some of its shortcomings.

With a free os: indefinitely

With a proprietary os: hope and pray the maker doesn’t discontinue it tomorrow

I’ve got a DS416 that I’ve had for almost a decade, and its still going strong. Worst thing I’ve had to deal with is a shucked easystore drive that died, but the other 3 are running fine.

I’ve bought a Synology DS415+ back in December 2014. So it just turned 9 and it’s still kicking. (Even with the C2000 fix.)

Although Synology stopped delivering updates, I’ll keep it as long as it does what I need it to. However, my next device will be a TerraMaster where I’ll install OMV on. Can’t get a NAS with custom OS in a smaller form factor.

What do you mean by “last”? I know it’s a common term, but when you dig deeper, you’ll see why it doesn’t really make sense. For this discussion, I’m assuming you mean “How long until I need to buy a newer model?”

First, consider the reasons you might have for buying a newer model. The first is hardware failure. Second is obsolescence - the device cannot keep up with newer needs, such as speed, capacity, or interface. The third is insecurity/unsupported from the vendor.

The last one is easy enough to check from a vendor’s product lifecycle page. I’ll assume this isn’t what you’re concerned about. Up next is obsolescence. Obviously it meets your needs today, but only you can predict your future needs. Maybe it’s fine for a single 1080p* stream today, and that’s all you use it for. It will continue to serve that purpose forever. But if your household grows and suddenly you need 3x 4k streams, it might not keep up. Or maybe you’ll only need that single 1080p stream for the next 20 years. Maybe you’ll hit drive capacity limits, or maybe you won’t. We can’t answer any of that for you.

That leaves hardware failure. But electronics don’t wear out (mechanical drives do, to an extent, but you asked about the NAS). They don’t really have an expected life span in the same way as a car battery or an appliance. Instead, they have a failure rate. XX% fail in a given time frame. Even if we assume a bathtub curve (which is a very bold assumption), the point where failures climb is going to be very unclear. The odds are actually very good that it will keep working well beyond that.

Also of note, very few electronics fail before they are obsolete.

*Technically it’s about bitrate, but let’s just ignore that detail for simplicity. We’ll assume that 4k uses 4x as much space as 1080p

TL;DR: It could fail at any moment from the day it was manufactured, or it could outlast all of us. Prepare for that scenario with a decent backup strategy, but don’t actually replace it until needed.