Maintenance

Software maintenance is usually a great part of software life. In my professional experience, it's not uncommon for a project to be fully active (with a lot of new features and developments happening) for a couple of years, followed by many years of maintenance, which is focused on fixing bugs and keeping the product alive (without releasing any new features).

It goes without saying that the maintenance period can become more expensive than the building of the project. Moreover, but this is a consideration purely from an economic perspective, enterprises often find it easier to access the budget for building new applications (which is seen as money generating, or at least associated with business initiatives) than for maintaining and modernizing older ones (which is seen as IT for IT, which means that this is a project with no business impact, hence, purely a cost).

With that said, maintenance activities on existing applications can be roughly categorized into...