It's hard to answer this question for sure with the limited information provided. If your broadheads are from last year and have not been used OR carried around in your quiver, etc, they should be fine indefinitely. But just carrying them in your quiver can dull them over time.
Having participated in multiple long, unsuccessful tracking adventures way back in the day I can say that the most important thing you can do is to use razor sharp broadheads. (These were not my deer we were tracking, but friends who would reuse broadheads over and over, even after being shot into the dirt and used for target practice, etc. They could never figure out why the deer were not dying immediately, etc.
A razor sharp broadhead...
1. Cuts more tissue and leads to more blood loss. 2. Does NOT alert the nervous system of the deer as much as a dull one. 3. Provides more/better penetration.
If in doubt, trade in for some new or well sharpened blades. Deer I shoot rarely make it out of sight and I haven't hit one and not retrieved it in many years. I know the sharp broadheads are a key reason for that.