Q: Maintenance Schedule

Other than Severe Driving Conditions (doesn't apply in my case), the maintenance schedule does not provide intervals for Transmission Flush, Differential Flush, Coolant Flush, or Fuel Filter Replacement. I know today's cars use longer-life fluids than my older cars, but is there some sort of preventative action schedule that should be embraced on these items? It does recommend that the fluids be inspected routinely (and my Yourmechanic does this) but my experience says that by the time fluids start showing problems, it's too late. Also, since I historically replaced hoses when I did a coolant flush, what would be a reasonable proactive schedule for those? Don't really want to wait until I have noticed deterioration or brittleness. Thanks for your help.

My car has 50000 miles.
My car has an automatic transmission.