Hi,

You wont find the solution for this in preferences, even though you can change the settings there for the project you are working on.

The answer you are looking for is to go to the "file menu", "new scene" (options)
Set your default working units and desired frame count there.

Now each time Maya opens or you make a new scene you will have whatever time code you set, Film/PAL/NTSC etc ....and whatever frames you set in the timeline.