There's a subtle reason that programmers always want to throw away the code
and start over. The reason is that they think the old code is a mess. And
here is the interesting observation: they are probably wrong. The reason
that they think the old code is a mess is because of a cardinal, fundamental
law of programming:

<<<
It's harder to read code than to write it.
>>>

Joel Spolsky
"Things you Should Never Do, Part I"