I harvested two final yellow squash, and then ripped out the plants. They were suffering because of bugs, and my treatments were enough to keep them alive, but they were not thriving. There are huge commercial fields of the stuff all around the homestead, and I can't control the untold billions of bugs that swarm around. Curiously enough, the Butternut squash, which is different species, is not host to the bugs, and actually I like Butternut squash better.
I went through something similar with the eggplant, but I killed the pests and the eggplant is flowering again profusely. It might be too late in the season for more fruit to develop, but here I'll take a success. I'll have one final harvest of eggplant this year, and I may leave the biggest fruit to go to seed for next year.
I'm on the fence about saving seed, because sometimes my seed is not viable and that screws up my growing schedule. I'm thinking about buying new, commercial seed every year, and modern hybrid seed, not heirloom.