Basic seed saving question.

Every year I tell myself I'm going to save lots of veggie, herb, and flower seeds. So far I have never managed it.  This has been a very strange year weather wise.  We always have mild fall weather, but this year summer just kept going.  Because of this I'm just now taking out my summer veggies.  
1) I grew foot long beans/ snake beans, what ever you want to call them.  They were tasty, grew well, and very productive, even with the super hot weather. A bunch dried on the vine. I would love to save them. They did have aphid twords the end summer. I'm wondering if because of this I should not keep the seeds.  I always have more to do then time (my own fault) so I don't want to spend the time to shelling and store them if the odds of germination are slim.
2) I have some eggplant that turned yellow on the plant. Are they good seeds to save, or am I better off removing the seeds from an eggplant we will eat?   I'm going to try to over winter a couple, but haven't done that before, so I don't know how that will go.
3) the last of the okra is still on the plant. Should I leave it until it's dry?  Would it be better to pick them and bring them in to dry?
I'm not going to bother with tomatoes. Yes I still have tomatoes ripening on the vine. It's finally getting colder, so I'm sure we are done. It was a terrible year for tomatoes for me. Most didn't turn red, and what did I was told tasted sour( I don't like tomatoes).  So even though they started getting red and tasting better this fall, I think it's better to just start from scratch.
I know I have to make sure the seeds are dry, and will store them in a paper envelope. If there's anything else you think I should know, I would love to hear it.  Thanks

I pick my bean seeds late a lot of the time after they have been dried on the vine for sometimes a month or two or longer, and have had really good germination so far. Some of them rot or get fungus on them, and I just toss those, and am in the process selecting for the ones that don't rot. Last year, the first year I saved the bean seeds about 50% had issues with rot and I tossed them. Just in the second year, this year, where I planted the seeds of the ones that didn't rot, less than 5% were damaged, and I got way behind on picking them, and most of them were hanging on the vine for over two months and only 5% had issues, so I'd say it's definitely worth it to save the seeds.

I pick my okra once they're dry and they are a great crop for producing tons of seeds in each pod and they are very easy and fun to collect the seeds. I didn't plant much okra this year, but I did have a few plants. This was also the first year of the saved seeds, and I had huge thriving okra that were a lot bigger and productive than last year. I think last year I averaged 4 or 5 pods per plant, and this year I had one that had more than 20 on it.

So yeah I'd say save those seeds! I did the same thing and never saved my seed for years, but now that I've started saving them, I don't think I'll be buying any seed at all this year and probably very little in the future! Plus the plants are becoming very tough and way more productive!

I'd keep eggplant seed from the ones you want to eat, not the ones that go bad.

Edit: Please ignore my advice, better answers are below!

I grew those beans before and they did pretty well. If I was purely growing them for the beans then it might not have been worth it, but I figured they helped to build the soil (sand) if I left the roots in the ground and composted everything but the beans. I had great germination, and in my climate I could go from seed to harvest 5 times in a single year.

Those things were absolute aphid magnets. Planting them around the perimeter seemed to help other plants not get attacked as much. So for me, the value of building soil and being a lightning rod for aphids was greater than the food value of the beans. Now that I think about it I don't believe I ever actually tasted one, I always replanted them.

If you eat your eggplant when they're still glossy and tender, the fruit are immature and unlikely to have viable seed. The ones that have gone yellow will have good seeds in them.

Aphids on beans don't have any effect on the genetics other than the possibility that they're a sign that the plants themselves were unusually enticing. The seeds will still be good.

I also tried saving eggplant from a nice "mature" eggplant and found the seeds were flimsy and not viable.

I later saved one from a half-rotted eggplant and about a hundred nice plump seeds. I haven't planted them yet, but they look just right.