Hello Guix!

After `guix pull`, I usually run `guix upgrade --dry-run` to check
which derivations will be built. If I find heavy ones like icecat,
evolution, calibre, kodi, qtwebkit etc., what is the general rule of
thumb waiting period for the substitutes to be available for those
packages, before I re-run `guix upgrade`? Assuming I will not be doing
another `guix pull` during the waiting.

Thank you!

Regards,
RG.