> My 10+ yr old Yaris is leaking some fluid (I forgot which), and the dealer said it would be $1k+ to fix it, I didn't know if I could even sell it for $1k, so I said forget it. Thankfully the car is holding up valiantly, but if the leak becomes worse there's a very good chance I'll just throw it away because fixing it is not worth the value of the car.

I don't understand why you are comparing the cost of fixing it to how much you could sell it for. Shouldn't you be comparing to the cost of replacing it?