If you're looking to keep ypur film ultra fresh, a fridge is good, but unless you've got it in the glovebox of a car in the sahara, keeping it at normal room temp is what is usually expected, and won't do any harm.
Really old colour film can be expected to colour shift a bit, and prehaps lose a little speed. XP2 super won't colour shift in the conventionally accepted way, but may lose a bit of speed. XP2 super can have a bit of a cast anyway (which is usually lost with a decent minilab) so nothing to worry about.
No store I've ever used has refused to process a film thats a year or two past its "best". The only problem would be if you shot something Really old like Kodacolor II which uses chemistry thats not used any more (C22 in that example)
So basically load up, and shoot. May be worth metering at ASA200 if you are worried about it being very old, but thats about it