The distinction between maintenance and Tech Debt comes down to whether the choice for an imperfect or expedient way of solving the problem was made consciously. You incur Tech Debt consciously to deliver value in the short term at the cost of not being able to sustainably deliver that value as parameters change.
Maintenance on the other hand is stewardship of a system as both the system(entropic decay) and it's environment constantly change.
Maintenance on the other hand is stewardship of a system as both the system(entropic decay) and it's environment constantly change.