What should be the size of a /boot partition for a manager like grub?
Mine is about 100 MB, which some would argue is too much. In case you trashed your distro and you still have /boot partition then you would be able to install one...change the grub config file to point to the disc/partition and correct kernel/initrd file and you are all set to boot your new distros. That is what I do. I haven't replaced grub for a while and I keep changing my secondary distro. Primary is, obviously, Slackware