I am replacing some footage with newer footage. I double-click on the footage to get my area bar in the timeline. I then place the footage in the area and find it is a little big. I go to trim it and it won't trim to the exact same place. I have tried holding down the SHIFT and doing it and also turing off snapping as well, but it doesn't seem to want to go in the exact same place...I have also zoomed in to see if that helps and it doesn't. Any ideas why this is happening?

My guess is that you had "Quantize to frames" turned off at some point, did some editing and then turned it back on again (or vice versa).
To see if the original had this feature turned on, go to the beginning or end of it and step through it a frame at a time.
If the cursor jumps past the beginning or end of it, you'll have your answer.

What I typically do is right-click, drag it to the event, and choose "Add as Takes". This lets you switch back and forth between the old and new.

Another thing you might try, though, is zooming in on the timeline.