My uncle repairs appliances. A couple of factors that he's encountered in his years of experience: 1. Energy star compliance. Many of the pumps now use far less power but are more prone to burnout. Keeping a fridge door accidentally open too long is much more detrimental to pumps than it used to be. 2. Firmware. Never been an issue with older fridges but it's now another point of failure.

There's certainly many more but those are some of the most common ones he runs into.