I was listening to a recent Stack Overflow podcast on technical debit and was getting progressively annoyed. The cause of the annoyance was that the speaker was lumping all changes that were not feature changes as technical debit. The changes he was speaking about are better characterized as either maintenance, evolution, or technical debt.
Maintenance is bug fixes. The original implementation is deficient and needs to be repaired. This work is only related to the original design and current feature set.
Evolution is change needed due to alterations in the runtime environment. This work is only related to the original design and intended runtime environment. For example, you need to update a library and that results in a need to update the original implementation.
Technical debt comes about when the original design is unable to accommodate a new need. For whatever reason, it is no longer suitable.
Too often "technical debt" is used to mask an organization's lack of timely maintenance and planned evolution. Don't do that.
