I change strings/cables every year whether they look like they need it or not.

I make all my own so it's easy for me to do.

A well made string with modern materials should not have a problem with stretching after a few break-in shots to settle it on the bow.

If you're going on a big hunt as you say, and it's been over a year on your strings, why would you want to take a chance of something going wrong on your hunt? Get a new string and save the one you're using now as an emergency backup.