Actually, Enterprise has a strict retirement schedule for RAM as well. Every 2-3 yrs I do believe. Also, keep in mind, Enterprise is more than likely going to be running server grade equipment as well.
If memory reliability is a concern (and if this is a server with 99.99999% uptime), have to go ECC and this is actually proportional to the amount of RAM that one has in the particular server as well. Chances of error with 4GB of RAM is different compared to 8, 16, and so on (higher memory, higher reliance on software that runs on memory). In the desktop space, this isn't much of a concern for a lot of people (if it was, I don't think overclocking would be a the thing that it is as that does increase the chances of errors, but maybe it still would be), it all depends on what the application of the
computer is, by I would say by far for most, that isn't an issue for a lot of people, certainly not to have to worry about the cost or hunting the deals etc.
Bitflipping is a thing and with ECC is better to spot and schedule service compared to just being surprised by the failure. Now, if this is non critical stuff, that's a totally different thing, don't worry about it. If this server isn't running all the time (mine are on 24/7) or if it is, but if the lifespan is already determined not to be that long (3-5 yrs), don't worry about it and if it isn't mission critical, even moreso not to worry about it.
I think the Qnaps run within that lifespan as well. I had one last 5 yrs, had another that lasted 10, but everything was going out on it (but these were older ones as well, I haven't bought a new Qnap in a long, long time, not that they weren't good, just needs changed). Board, controller, everything, it definitely lasted and got my money out of it.