It varies based on context and how much thought I put into it. I might just think apples and not image them if its just a place holder but if Im thinking more about apples or like a scene in a book is engaging then the apple will be there in the visualization but how detailed it is is going to be based on its importance in whatever the thing is. I would have to be really trying to visualize the perfect apple to get a high detail one in my head. I used to read a lot and I feel like I visualized a lot more then but now that I am consuming media that just has the thing its like im not working out the muscle.