I always have several bows ready to roll at a moments notice. And we're always sure we have at least one backup bow on out of state trips (the people I hunt the most with shoot the same specs as I do).
Ive only needed a backup once in over ten years of out of state hunts, and it saved my ass on that trip.
With the money guys invest in hunting, $800 packs, ultra-spendy camping gear, four digit prices on tags, years worth of applying for tags, gas, and most importantly, vacation time, I think its stupid a guy NOT have one. You can pick up some pretty nice bows that are 4+ years old and VERY capable of being a back up bow. In the long run, its cheap insurance to protect a much bigger investment in an out of state hunting trip.