I’ve definitely seen The Prestige (2006) the most in my adult life, it was my taste-barometer when showing a new friend or date when I was in my 20s.
But we had the The Mummy (1999) recorded from TV on a VHS growing up and I recked that shit. I probably watched that film 30-40 times, between childhood days off sick and rewatching intermitently in adulthood.
Honourable mention to Love Actually; thanks mum.
By choice? Monty Python and the Holy Grail or Fired Up. I watched them both roughly monthly for a half a decade and could recite them both nearly line for line in high school.
Under duress? Spirit: Stallion of the Cimmaron. It was the only movie in my dad’s SUV for about a decade and I’ve probably seen that movie more times than literally anything else because of that.