In the garden I think the trick is to find a balance between what you like to eat/can be stored, what is easy to grow and what is expensive to buy. You might also find that some things just don't work for you at all - for example I've now given up with sweetcorn and spinach as they either don't grow or get eaten by pigeons for me.
I grow new potatoes, broad beans, french beans, peas and runner beans, plus courgettes, so from July onwards to October I don't buy any potatoes or green veg. Any surplus goes in the freezer - even spare courgettes are diced and frozen to bulk out soups in winter. Peas in their pods are also a great treat for DD in her opinion. We have also inherited an asparagus bed, though I wouldn't have bothered with this otherwise. For winter we have parsnips and leeks growing, plus purple sprouting if it makes it through winter.
For salads I grow spring onions, cos lettuce and radishes in the garden, plus mint, rosemary, tarragon, chives and parsley in pots by the door. I've never been able to manage carrots as these seem to be eaten by some sort of weevil, and rocket and spinach bolt every year with me. Again, from June onwards, we don't buy salad until October ish.
We also have blackcurrant bushes, strawberries, raspberries and some small fruit trees. We live in the north, so have a greenhouse for basil plants, cucumbers, gherkins, tomatoes, peppers and chilis.
I've found it vital to deal with ripe crops as soon as possible else you just have this mountain of green things to deal with which feels like another chore to do. At the moment I'm roasting tomatoes with garlic for a sauce to freeze, and also freezing chunks of strawberries for use in flapjacks etc later on. DH has lots of smoothies with our fruit, so again it is easy to have a tub in the freezer and throw any spare berries, brambles or left over banana in there for use later.