Life Expectancy of Vegetable Seeds

      It is about that time of year to get some veggies started indoors for their eventual move to the porch, cold frames, or vegetable gardens.  It is also time to review what seeds I have on hand, and then to make a seed order to replace empty stocks or to try something new.  Recently though, on some internet searches, I have run across articles discussing the life expectancy of vegetable seeds in storage.  There are lots of references, this one is from the Iowa State University Extension site:

http://www.ipm.iastate.edu/ipm/hortnews/1999/4-2-1999/veggielife.html

Approximate life expectancy of vegetable seeds stored under favorable conditions.

Vegetable	Years	Vegetable	Years
Asparagus	3	Kohlrabi	3
Bean	3	Leek	2
Beet	4	Lettuce	6
Broccoli	3	Muskmelon	5
Brussels sprouts	4	Mustard	4
Cabbage	4	New Zealand spinach	3
Carrot	3	Okra	2
Celeriac	3	Onion	1
Cauliflower	4	Parsley	1
Celery	3	Parsnip	1
Chard, Swiss	4	Pea	3
Chicory	4	Pepper	2
Chinese cabbage	3	Pumpkin	4
Collards	5	Radish	5
Corn, sweet	2	Rutabaga	4
Cucumber	5	Salsify	1
Eggplant	4	Spinach	3
Endive	5	Squash	4
Fennel	4	Tomato	4
Kale	4	Turnip	4
		Watermelon	4

Table modified from D. N. Maynard and G. J. Hochmuth, Knott's Handbook for Vegetable Growers , fourth edition (1997)

      Some veggies that I had a tough time germinating last year were onions (poor), parsley (poor), parsnips (zero), spinach (poor), and leeks (poor).  Three of those five show up as to having just a one year seed life expectancy.  Now, my usual plan is to buy the leftover seed from the past year when it goes on sale for 50% off packet price.  Not such a good plan if it results in lousy or zero germination.
      I just went through my rather huge piles of seed packets to retrieve those seeds with short life expectancies.  I am going to plant ALL of those seeds shortly to see what happens.  And buy fresh seed to plant for items I particularly want, such as Walla Walla onions.  I am finding that the cold frames are great for extending the fall greens harvest into winter, but I need now to get started on planting to look ahead to the spring gardens.
      A different reference suggests that spinach seeds are very short lived:

http://growingtaste.com/storage.shtml 

These folks are suggesting just one year for spinach rather than the three years suggested by the Iowa reference.  My experience with poor germination of spinach either in cell packs or sown directly, would support this second reference.  Maybe using fresh spinach seed would finally result in a decent crop.  And another thought.  Is the quality and viability of a plant that does germinate from old seed less than that of a plant germinated from fresh seed?  Even the spinach plants that I have been able to germinate have had short lives before succumbing to some insect pest.  So all of the spinach seed on hand gets used or trashed as well.   Maybe I can reduce a lot of packet clutter.