In all my years of building PCs I've only ever looked at a QVL for ram once or twice and I think they were for server builds.
Server builds would certainly warrant an extra level of caution, even if it is just superstition...couldn't tell by me, I don't build servers.
But, I also have the general notion (superstition?) that OEM desktops (Dell, HP, etc) are a little more finicky with RAM compatability than aftermarket mobos. Of course, that hasn't stopped me from mixing and matching RAM from multiple manufacturers that I have sitting around into recycled Dell systems without any negative consequences. If I'm buying
the RAM for those systems, I'm more choosey. Mostly because I HATE returning online purchases.
said though, finding the exact matching numbers corresponding to the QVL is oftentimes a wild goose chase even if you have the best intentions.
Main: i5-3570K, ASRock Z77 Pro4-M, MSI RX480 8G, 500GB Crucial BX100, 2 TB Samsung EcoGreen F4, 16GB 1600MHz G.Skill @1.25V, EVGA 550-G2, Silverstone PS07B
HTPC: A8-5600K, MSI FM2-A75IA-E53, 4TB Seagate SSHD, 8GB 1866MHz G.Skill, Crosley D-25 Case Mod