One job I had, we got handed a code base with at least 4 different reinventions of an ORM in it. It became clear that each developer who'd worked on the code h

One job I had, we got handed a code base with at least 4 different reinventions of an ORM in it. It became clear that each developer who'd worked on the code had written their own helpers to avoid direct SQL. It took a fair bit of persuading leadership, but the first task ended up being doing a huge reactor of everything SQL. Unsurprisingly enough, lots of bugs got squashed that way.