I have never once have I had to descale my showerhead or faucets due to my city's water quality

I don’t think scale represents “bad” or even “low” quality water.
- It does not. Hard water tastes delicious
  
  Also it gives the morning coffee that lovely crunch.

Guessing you live next to a lake then, scale comes from groundwater. Or your city is rich enough to pay to soften it at the treatment plant
- It isn't lake/rive vs ground water. It is about what the water goes through / touches. Places where the water touches limestone will get lime scale. Some wells have more scale than others. Some lakes have very hard water. It is about where you live.
- River, but we have a massive water treatment plant that feeds the city.
  Just recalled going on holidays and seeing how bad some showerheads were with all the scale buildup. Just clicked in that I've been spoiled with our water quality and has never been an issue
  
  Good water can have minerals that cause scaling too. Soft water removes the things that make water hard, but doesn't necessarily mean the water is of a better quality as it could have toxins or other stuff in it.
  
  That's not how this works, that's not how any of this works.
- It could also be mountain runoff.

I don't even know what that is...
- What is?
  Bathing?
  
  Bathing
  Wahaha, so funny, funnyguy... I meant descaling. Descaling a shower-head or faucet. Never heard of that.

Arizona has super hard water. My 3 year old bathroom faucet already needs it.
- Oh wow, looks like average 250 mg/L (ppm) except for bullhead city which is a whopping 619 mg/L (ppm)!
  I'm at 30 mg/L (ppm) of total hardness. I couldn't imagine 600. Would feel like sand paper water I bet
- I have to descale my kettle twice a week. It's so fucking bad.

Me too. Never had to do that.
Its actually not due to the quality itself... But the lack of scale (hope its the right word) in the water.

About once a year I'll soak my shower heads and faucets screens in vinegar to get rid of the mineral buildup. Other than that, the water tastes great and tests perfectly healthy. I just wonder what it's doing to my house's plumbing.

Me either. Though I probably should because it's probably cheaper than replacing the shower head every couple of years. 🤔

That's great! I think we need to pay close attention to our water supply and I appreciate that you are posting a positive take.
We have good water here, though it is the most expensive municipality in the country. The elevated price comes from our long-ignored sewer infrastructure and the layer-cake of band-aids that we are paying for. That said, we have steady rainfall and plentiful aquifers. Water here is almost taken for granted (except for that sewer bill, which is calculated on water consumption).
Even still, I have whole house paper filters to pull the iron out before it gets to any faucet, then a second stage of carbon filters for drinking water. Cheap to install and easy to maintain and it goes a long way to improving our water quality. I don't know if you are using any other filters, but you can quickly turn an A- water experience to an A+.
- No filters at the house, have never even considered house water filters until those door to door (I call em scammers) came around selling house filters. Our city proper doesn't need em which is why I say scam.
  The citys last report shows pretty low levels of bad stuff across the board and it's very soft water. Showers elsewhere feel weird..lathering soap is 'harder' and I feel like I'm extra dry while showing in hard water? it's weird to explain.
  30 mg/L (ppm) of total hardness
  Total Chlorine 1.88 mg/L 1.72
  Fluoride 0.68 mg/L 0.52
  Boron mg/L 0.0056
  Cadmium mg/L 0 0.005
  Chromium mg/L 0.0001 0.05
  Sodium mg/L 12.0
  Fluoride mg/L 0.68
  Nitrate mg/L 0.18
  Haloacetic Acids* mg/L 0.027
  Trihalomethanes* mg/L 0.033
  Anything not listed is zero, and all are below our provincial standards

I never have, and I can see a little buildup, so I may at some point, but we've been living there almost ten years now, so I think we're doing alright.

I live in Australia
In my town which I will not mention because I don't want to dox myself the water tastes yuck and leaves limescale on things