Keep, improve or replace your existing software?
Old software can be expensive to change and still contain business knowledge worth keeping. Its age tells you to investigate; it does not decide whether to replace it.
Name the constraint
Separate a slow user task from a slow development process. A page that loads badly, an integration that repeatedly fails and a product that takes months to change may need different interventions.
Describe the operation to measure and the conditions of the test. “Make it faster” leaves too much open. “Load a customer’s order history with this volume of records” gives the team something it can investigate and repeat.
List what depends on the current behavior
Include reports, scheduled jobs, exports, permissions and manual checks outside the application. Ask experienced users which exceptions the documentation leaves out. For every dependency, identify an owner and a way to check it after the change.
Compare the transition, too
Keeping the system means accepting some maintenance and limits. Improving it may remove a specific constraint. Replacing it adds migration and reimplementation work. A staged replacement also creates temporary responsibilities for data shared between old and new components.
MERP/PREP required a full rewrite across web, mobile and backend, with DevOps and migration in the same engagement. That scope followed the product’s needs; it is not the default recommendation for every older application.
A useful modernization assessment should explain what to retain, improve, replace and retire, along with the evidence that could change the recommendation.
