Oil change

[Nima]

Hey everyone:
I am in the middle of moving from one place to another therefore I don't have that much time to spend on my truck at these days,unfortunately.
Anyways, there was a thread while ago about different types of oils for these older trucks/engines. It was my undrestanding that most of you prefered synthetic or high milage oils. Now, my question is; I tought oil's job beside lubrication is cleaning the engine, if you use high milage or synthetic oils, how often do you change them? Isn't it better just use regular 10-30 oil but change it more frequently since I aaume these engines make the oil dirty faster?
I appreciate any input.
Thanks