Did a drain and fill on tranny... oil looked new...

My '07 has 113k , i've never changed the oil on my transmission. When i had my differentials done at 100k i asked em to do it but they said they wouldn't i had to take it to nissan. They were scared of the bolt on the dipstick, like it was a special lock from nissan. ha I remember calling nissan and it being outrageous so i was going to do. Well i kept pushing it off because i was "about" to get the transgo kit and kept pushing it off. After reading that the manual says every 30k i kinda got a little worried. So i changed it today and emptied 5 gal into a clean container. I then poured it into a little clear plastic cup. It looked brand new and smelled like new. I'm not mechanic other than my driveway stuff but i think every 30k is an overkill. Maybe 50k...... i dunno i did some towing the first 100k but haven't the last cpl years.