Brake fluid does NOT need to be replaced every two years nor even need to be checked in normal driving. Source, 65 years of driving keeper cars that never had brake fluid changed. I don't know where this comes from unless it's people who overheat it at tracks. Let the argument begin.
It comes from basic chemistry.
Brake fluid is hygroscopic.
It absorbs water from air simply by existing.
There's folks who don't change their transmission fluid ever too and just get a new car often enough to never have a problem- doesn't mean it's a good idea overall.
DOT4 absorbs water slower- but the boiling point drops a lot faster when it does (with a 50% drop in boiling point at just 3% water)
Think about how much effort Tesla has put into NOT having routine maintenance items. Yet brake fluid remained on the list.
If the engineers who built the car think it's important to check they might be on to something.
Important to note what they're suggesting every 2 years isn't a CHANGE though- it's CHECKING if you need a change.
Because depending on use, climate, etc you might need a change at 2 years. You might be fine till 4 or 6 years.
But basic chemistry tells us unless you live in a desert you're probably pushing your luck too much after that. Given you live someplace super humid I guess you've been lucky to now or just replace cars often.