I do mine every 5000 miles that way I can keep up with it easier on the odometer. Mobil 1 and a Wix filter for me has been the way for 20 years now and several, several vehicles.
Mobil 1 5/30 and a Wix or AC Delco filter every 4000-5000 miles. Usually around 4K I start telling myself I need to get it done so that gives me a little time.
I no longer use 15w50 in the 96. It currently has mobil 1 full syn with a mobil 1 filter too. The Xterra also currently uses the same. Next oil change however The 96 will get Mobil 1 EP with the Amsoil filter and the Xterra will get the same. Then after 10K ima do a ful switch to amsoil on both.
Normally change mine around 5K since I switched to Amsoil OE. I use to change it every 3K when I was using Valvoline...even full synthetic.