1hr+ for a general update* (following the guide. Pre-kernel)
On a more serious note, gentoo is fun… On competent hardware. This is a 4 core Celeron N2940 with 4gb of RAM.
*emerge --ask --verbose --update --deep --changed-use @world is too long to type…
I think that’s more for when you have multiple machines (that would use the same USE flags) and you only want to have to compile once. OP’s use-case re: binary packages would be more about getting them from somebody else (i.e. a public binhost that already exists) so he doesn’t have to compile at all.