Often the reasons are not clear because they are not documented it, often only the dev who did it would really know. Also, it's probably worth taking note of '

Often the reasons are not clear because they are not documented it, often only the dev who did it would really know. Also, it's probably worth taking note of 'fresh eyes' because they have the advantage of hindsight which is often good. That said, there usually complex elements of incumbencies so I do think it should be some time before people have too much lean in.