Having listed these three common reasons, there is a fourth one that all business owners should consider, and that is obsolescence issues impact user adoption and commitment to their CRM software. Consider the following experience we had with one customer.
We approached this customer last fall to encourage her to upgrade before their existing ACT 2012 version became obsolete. We had a few discussions back and forth, but ultimately she refused to upgrade because only half her users were actively using the software. Her reasoning was she wanting the adoption level to increase before she invested further. On one level I understood ger point, but her decision will likely lead to the opposite outcome. As the obsolescence and compatibility issues begin to plague her employees, she'll begin to lose her existing active users, and the non-adopters will have their resistance vindicated. The inevitable outcome of this scenario is this customer will be forced to start from scratch at some point in the near future, and begin the cycle all over again. To make matters worse, her employees become less productive, less accountable, and less organized during her learning curve.
This is a cautionary tale for business owners hoping to save money by not reinvesting in their mission critical business applications. Like a car, if you drive it into the ground you'll inevitably be forced to make a much bigger investment than if you had maintained it properly.