I do it pretty much on my own for https://ossia.io ; it takes me roughly a day every other month to update my mac, linux and windows SDKs to the new LLVM / Qt / FFMPEG / {... other large dependency I use ...}.
Definitely not the end of the world. Said SDKs & build scripts are available here: https://github.com/ossia/sdk for anyone interested (I'll be honest though: the scripts are a mess!)
1 day for... ~500 kLOC, it seems. Which is pretty good I think, but larger codebases would have a lot more to deal with -- not just more dependencies, but also more breakages per dependency.
Definitely not the end of the world. Said SDKs & build scripts are available here: https://github.com/ossia/sdk for anyone interested (I'll be honest though: the scripts are a mess!)