I do my upgrades every few weeks, for what it's worth, and I've had the same Arch install since 2013. The size of the upgrade should very rarely have any effect on whether it succeeds; you're just more likely to have missed some major changes if you're upgrading without checking the latest news from the website.
Partial updates are also unsupported, and in my experience that's the most common way people break things.
Thing is, I'd only want such an install for playing around with occasionally and as the argument upthread makes pretty clear, "doing a bulk upgrade occasionally" is something that really isn't regarded as a sensible way to run arch.