So I have had my P4 for awhile and though trouble free with not as many Kms or hours on it as some folk I think its time to look into maintenance. I inspect it often, nothing else to do with the rain, but I was wondering what those more experianced flyers do to maintain their birds? After so many miles on my car I neglect to do stuff but this is my drone, should I change the oil? I see a lot of people just upgrade to the next model as they seem to come out faster than I can crash a drone. So those users that have been using their drones for many hours is there things you do to keep them flying? Props look good and all is fine but I want to keep it that way.

I use to bend up the spring thats holds the propellers after about 15 hours of flying. Like in this movie

Apart from inspecting it for obvious cracks, not using solvents to clean it, and as said above, checking the springs, there is not much you can do.
The motors are brushless, so they will last as long as the bearings last, if they don't burn out before. The bearings are sealed so you cannot get to them to lubricate them easy, but they will last as long as the life of the copter if you don't fly in very dusty conditions.
You can take care not to snap the battery in to hard, press the release buttons even when you put the battery in, to minimize mechanical stress on the clips, and always put the gimbal lock on when the copter is not in use, or when transporting.

Thanks, I did not see very much I could do which is why I asked.