I have hunted the same farm for 20 yrs and I worked the farm as well............I just know my woods and know them well. I don't recall anyone that has changed how I do it, I just learned on my own really.
I am in very similar situation. I have hunted my primary hunting spot for quail and turkey long before we even had deer on it. Although we hunted sdeer down state when I was a kid, I really didn't know much until I started hunting back in the mid 80's on our own property when we started seeing more and more deer in the area.
My primary hunting property is roughly 300 acres and like you, I literally know every square foot of it.
Where we differ it seems,is in our approach to hunting these properties. Granted, I already know bedding areas, travel routes, early season feeding patterns, late season feeding patterns, etc., but every year I am still learning something in regard WHEN to hunt, HOW to enter and leave, Wind direction, inclement weather adjustments, rut tactics, etc, etc.
Some of my new tactics are things I think of myself but mostof these things I experiment with because of something I read or heard from someone else. Not anyone in particular, just a cumulation of a lot of people/resources.
The way I hunt today is so different than 5 years ago as it was so different than the 5 years before that.
As has already been mentioned by others, when I get to the point that I don't think I am learning something new and improving in my approach to hunting, that is when I will find something else to do.