Creating a garden suitable for real use is a huge learning experience, rather than a simple matter of planting a few trees.
The dry weather recently, combined with lack of water tanks and the cost (time and money) of watering by hand means that several of my trees have been suffering - primarily the non-natives that are not drought-hardy. Or trees that I've only just planted. Or seedlings that need to be planted (although I have been hand watering those). Then there is the question of - do I bother trying to grow a grain crop? I have barley seeds sitting there to be sown, don't have wheat, but will time and effort will be needed for them be worth it?
A little research goes a long way...
I've been reading up on sorghum - drought hardy, needs less water than other grains, can be put to a wide variety of uses. Moringa is a tree that will even handle arid areas, has many uses. Even something I had thought of mostly as decorative, Xanthorrhoea, has resin that can be put to industrial use if you know it's there.
My plan for long term survival scenarios is centred on learning what is around that I can put to use when there's nothing left to be bought on the shelves...