I dont know any concrete techniques. My applied rule of thumb is that 15-25% of total effort is/should be spent on maintenance and operations. Commonly called “

I dont know any concrete techniques. My applied rule of thumb is that 15-25% of total effort is/should be spent on maintenance and operations. Commonly called “keep the lights on” (ktlo) where Im at. Trending higher than that is a warning sign and probably unsustainable. Additionally immediate “post launch” support/additions/refinement can easily be an additional 50% of the original effort needed to make the “launch” goal. In both cases try and sort out the work that is directly associated with delivering the feature vs incidental/adhoc/subsequent improvements. You can use that course estimate for general budgeting. Finding commonalities across features/components will get you closer to your matrix or checklist to apriori plan the true cost per feature. PS it occurred to me that “operational readiness reviews” might help you discover or evaluate some of these unplanned costs.