I started reading “Working Effectively with Legacy Code”.  Here’s a great quote:

In poorly structured code the move from figuring things out to making changes feels like jumping off a cliff to avoid a tiger. You hesitate and hesitate. “Am I ready to do it? Well, I guess I have to.

Avoiding change has other bad consequences. When people don’t make changes often they get rusty at it. Breaking down a big class into pieces can be pretty involved work unless you do it a couple of times a week. When you do, it becomes routine. You get better at figuring out what can break and what can’t, and it is much easier to do. The last consequence of avoiding change is fear. Unfortunately, many teams live with incredible fear of change and it gets worse every day. Often they aren’t aware of how much fear they have until they learn better techniques and the fear starts to fade away.