Reusing a project


What is the best way to reuse a project: in the new one, one wants to reuse the schematics with all its parts with party # and footprint but must have a new name. In some cases, may want to reuse an existing pcb ( of course with the same netlist).?
All my efforts have caused problems including the loss of important designs. archiving does not seem to be a solution because the schematic file seems to refer to the old one & you change it in the archived version, all trouble will come about.

KiCad/demos/pic_programmer bad board layout