I have a 1996 Honda Civic 126,000 miles
I get my oil changed every 3,000 miles.
Tires rotated every 7500 miles.
Just had a new timing belt put on and transmission fluid changed.
Question: how often should I have tramission fluid changed? (I’ve been hearing different things lately. I’m from the 30,000 mile school of thought)
And are their any other regular maintence things I need to be doing to keep this thing run till 250,000 miles?
Everything you need to know is in the owner’s manual. There is a maintenance schedule, which will tell you how often to change all fluids, including the transmission fluid. In case you don’t have an owner’s manual (everyone should) check Books4Cars.com for an inexpensive used one.
Changing the oil every 3,000 miles is not really necessary. The manual probably lists 7,500 miles, and if that seems too long to you, you can easily go 5,000 miles, which is the interval at which I change the oil in my '97 Accord.
If you follow everything in listed in the owner’s manual you should be good. Modern cars do not need their oil changed as often as the older cars and older oils. Frankly most test indicate that the miles listed by the manufacturers is very conservative.
Most people suggest somewhere between 50,000 and 100,000 for the automatic fluid changes. I would suggest the 50,000 myself even if the manufacturer does not list it.
It sounds like you are putting on a lot of highway miles and those are easy on a car.
Good Luck