For once I am 100% behind DD here. I moved onto a new site 2 years ago, the first thing I did was to go and ask everyone about what types grow well on the site, the last thing I did was to completly ignore everything that I was told and grow the stuff they told me was not good and waste time and effort, I asked advice, listened and learned and grow the crops that grow well on our site.
The dates on the packets are there for a reason in that they give an indication for the optimum growing conditions of the plant, tried and tested over the years.
In the years I have been growing veg I learned the easy way, I asked and listened rather than did!