How many cases from the previous release you wrote will you add to the regression model in the current release?

Regression testing typically includes all cases that cover the functionality affected by changes in the current release, as well as critical and frequently used scenarios from previous releases.

That is:

• All new tests written for new features are necessarily added.
• Cases from past releases that test changed or dependent components are selected.
• Tests that identified bugs in the past should also be included to prevent their recurrence.

Thus, the number of cases from the previous release that will be included in regression depends on the scope and nature of the changes, but it is usually a significant part to ensure product stability.