also, one key aspect is. There are may be individuals out there that can do this. however, usually code is written by multiple people. (and i would also count

also, one key aspect is. There are may be individuals out there that can do this. however, usually code is written by multiple people. (and i would also count your future self as another person). that collaboration on the same code base requires automatic tests, otherwise the next person will break the code in non-obvious ways.