Do you have a package being built from source instead of bottle? Brew upgrade takes less than ten minutes or so for me. Things that influence this will be the

Do you have a package being built from source instead of bottle? Brew upgrade takes less than ten minutes or so for me. Things that influence this will be the amount and size of your installed packages and whether they have prebuilt binaries ("bottles") or if you need to build them from source. The latter is on your package maintainers.