The first year I still attempted to save cucumber seeds (because it's like the easiest vegetable) but the seeds weren't viable the next year when I planted them. I suspect that 1) the cucumbers most probably cross-bred with their squash neighbours in the garden 2) the pollination didn't happen because we just don't have any bees around here 3) the seeds were too dry.
Last year, I saved some runner-beans seeds. I still don't know where I will plant the seeds because don't want my bean crop to fail if the seeds aren't viable, so I might just try them in a pot. I also saved my potato harvest to use as seed the next year.
So I'm slowly learning about making sure my plants don't cross-pollinate with other plants of the same family. Which reduces the variety of veggies I can plant in one season. I either limit myself to one variety in each family or scatter the planting to make sure they don't flower at the same time.
So this year I'm taking this seriously as I'm planning my garden. I will plant only one variety of the annuals like tomatoes, corn, beans, lettuce and broccoli. But I might plant 2 varieties of each of the biennials (I have the seeds) like carrot, turnip, beets and onions, and see how I do. This way I could see which one does best in the garden AND in the root cellar. And next year, plant the varieties of biennials that did best for the flowering/seeding season.
And another added bonus this spring is the arrival of our bee hives, and my mom and partner are moving in. Their added help and support will be greatly appreciated and our seed saving ambitions might become possible.