How Long Will a Radiator Last - With proper service.

If a person follows all recommended procedures and changes coolant
on schedule, uses MB coolant, and flushes - how long would a radiator last ?

And if it will not last, what is happening inside ?

My coolant looks clean and healthy.
To me - unhealthy coolant looks like rusted water.

I could be wrong, I have no scientific evidence to back up what healthy coolant is.

So, I wonder if all radiators eventually have particles of crud that break loose
from the cast iron parts and eventually clog the small passageways.
Causing heat problems even though the radiator looks basically clean, and the
coolant looks good too.

I have no way to flow test a radiator, and most radiators shops I have been to seem to just boil and flush.

Over the last few years I have replaced radiators and water pumps in several
cars and it seemed like a new car when it comes to cooling.
I am starting to use the approach as standard maintenance.
I do it as good practice. I can't test the flow rate of the radiator, so I guess it is faith.

But if I could start hearing from folks that there seems to be a lifetime with a radiator, even under perfect conditions - then I will just change them at intervals based on age.

Any thoughts ?

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80 300D 340K Owned 30 yrs
83 300SD 440K Owned 9 yrs - Daily Driver 150mi/day
02 Z71 Suburban 117,000
15 Toyota Prius 2600 miles
00 Harley Sportster 24k
09 Yamaha R6
03 Ninja 250