[xupybd]

You often can't. Also don't assume the original why was correct. Instead learn the problem domain so well that you can make your own judgements.

[mierz00]

This also goes the other way too, you don’t assume the original is incorrect.

I see this a lot with developers who come in and start to criticise before understanding.

There is always a reason for why something is as it is, and it’s unlikely that the people before you were just idiots.