For me its a bit different:
Im ready to leave at 5PM after work.
i know im on vacation when my alarm rings the next morning
I know i can start relaxing when i feel the plane accelerate at takeoff (im a bit of a plane buff)
I know in Orlando when i grab my luggage and i walk though those sliding glass doors at MCO and get hit with the warm humid (or cool humid if its in the winter

) air.
I know im nearing home when everything suddenly turns to a lovely shade of green as you get to the Disney owned property
But only one thing reminds me that im home:
When the security guard says "Welcome Home", and when the front desk CMs do the same thing.
Call me weird, Sure everything mentioned here reminds me im in WDW, but its those 2 words said by the security guard that really makes my vacation!