Should I replace trasmission fluid and filter? Older car, gears are slow to shift and very rarely stick.

I have had my 93 Nissan Pathfinder for a little over 6 months now. Most past maintenance is unknown, so I have begun to do routine maintenance in order to start a history. I've recently replaced the oil, oil filter, air filter, fuel filter, spark plugs and spark plug wires. I've also begun to add Lucas fuel injector cleaner each fill up, because the gas in Atlanta can be spotty at times.

The current issue at hand is whether or not I should replace the automatic transmission fluid and filter or not. Its an older car, so I try to drive it gently, and give the gears time to shift. My wife on the other hand, the primary driver, thinks it should just go from gear to gear as fast as possible. She told me today when she was driving, at one point the gear was really slow to change but eventually shifted. I'm going to take it for a drive in the morning to see if I can duplicate this event or not. But I thought I would ask you guys whether a fluid drain and filter change would be worthwhile, or maybe even have someone take a look at it?

Thanks