This is the power of teams of software developers. When it comes to maintenance, if each team member remembers the same 40% and a few team members each uniquely

This is the power of teams of software developers. When it comes to maintenance, if each team member remembers the same 40% and a few team members each uniquely remember 5%, then the team has only forgotten a small percentage of the code and can work together to produce those "Oooh now I remember what this is" moments.