For a 10-day hunt, I usually take 15-18, although I've never come close to using them all. Incidental animals & birds, follow-up shots on wounded animals, etc. can all take more arrows than expected. Although, the number of broadheads is probably more crucial than arrows since you can often re-use arrows (if carbon) even after taking an animal with them. Broadheads are more hit or miss on the reusability, and if you're shooting expendables they are obviously one-and-done. Make sure to wash them thoroughly when returning home. The inspectors when returning to the U.S. aren't fond of finding blood on any of your equipment.