And I still have some difficulty with her thinking. She will take garden clippings to the dump in the boot of her car rather than having a bin that some guy removes (which would be cheaper overall). I know that generation had to live through hard times but she hates paying for anything.
Does she drive herself, or does somebody (you) drive her? Maybe she likes the company.
My mother used to get up in the middle of the night to go to the bathroom, without turning on any lights, just to save a few cents a year. That practice wound up killing her. Early one morning she went to sit on the toilet in the dark, and wound up on the floor. She died three days later, from complications.
Take care of your mother.
My Mom (85) makes my sister drive her across town so that she can use a 10 cent coupon. She saves the 10 cents and my sister spends $3 in gas and an hour of her time. Of course, part of it is an excuse for my Mom to get out but it drives her crazy to “waste” that coupon.
She’s my Mom and I love her but sheesh. Don’t get me started on all the pie tins and empty jars in the garage.
She drives herself.
If she is 86 and drives herself, just let her do whatever she wants, before she kicks your ass. 
I’m 81 and I don’t see anything wrong with that. 
Too bad I don’t live down there, or I’d ask her out on a date.