Often during emerging for ROOT=/prefix/... the same package is first build for ROOT=/ and then again for ROOT=/prefix/... It would be nice if portage could reuse the previously build binpkgs. Possible problems: * The build for ROOT=/ happens during the same run of emerge. Hence no dependency recalculation happens in between. Possible solutions (alternatives): * Know in advance that a binpkg will be build during a certain step and consider this for the following steps. * Search in each step for binpkgs before starting the actual merge. * ... your idea ... Reproducible: Always