Set it to zero when you break something.
Edit to add: you should be able to get some praise (or at least self-praise) at milestones like 30/60/90/180/365 days without an incident.
The results are just as you suggest.
Personally speaking I'd like to work at the software equivalent of Toyota. Where the whole organisation is constantly looking for feedback about development processes and how barriers to quality can be removed.
I think the problem is that how to get credit for the not having problems in the first place.
Oh this is very true. I've achieved a pretty good reputation in my org getting called in when things have gone wrong somewhere. Not so much for typical day-to-day work.
- Sun Tzu
The "hero" part of the firefighter comes from the fact, that they actually go towards real danger as part of their job, they often do unpaid and voluntarily. (A big fire out of control, is a very scary thing)
While the maintainance worker is usually not in danger, if he does his job right.
" It's a cultural issue that is very hard to combat."
So I do not really see a issue here to combat (when using this metaphor). The actual firefighters deserve their praise.
And if some companies are too shortsighted and praise the people heroically fixing their own mess, then I would use a different metaphor there, to adress this.
Clearly there are companies praising heroic fixes, while not praising too much regular maintenance.
But I think it is wrong, to talk down the job of actual firefighters, because:
"Clearly there are companies praising heroic fixes, while not praising too much regular maintenance"
that is a seperate issue.
Of course not all tech debt is bad, the trick is know when to use it to good effect, not building it up everywhere only to pay it back at the costliest moment. It's all a balancing act.