I live 10 minutes from my mother who is in a retirement condominium neighborhood. I have a sibling who lives 2000 miles away and another that is only an hour away. Both of my siblings still work. My mother has just given up driving. I go to her house one day a week to take her to appointments, to get groceries, etc. She wants to know my schedule in case she needs other things. I want to protect this retirement time that I have worked so hard for. Mom doesn't really require much from my other 2 siblings. Help!
I rely on one of my sons quite a bit for household help. I don't expect him to share his schedule with me. I'll email him and say such-and-such needs some attention. Could you have a look at it when it's convenient? If he responds, "The earliest I can get to it will be next Thursday," then I can decide whether I can wait that long, or should make other arrangements. He doesn't owe me an explanation of why he can't do it until then. (And if it is a big job, I pay him his hourly rate. He is a handy man.)
Set boundaries right from the start.
I, on the other hand, don't like to schedule my time. I like to play it by ear. Consequently, my mother thinks she can call me at a moment's notice and I'll be available. What I had to do was move away (an hour away) to make myself less available. As she grew more impaired, I also had to find other help for her day-to-day needs.
I would suggest that you involve your siblings early and often in your mother's needs. Right now she only needs transportation, but as time goes on she will likely need help with bills, housework, meals, laundry, and lots of other things. If she can't pay for help you are going to on the hook for all of it, unless your siblings are willing to chip in and share the cost of some of this assistance. If your mother does have money, insist that she use paid help rather than expecting you to take on the whole load to save money (or because she's rather have you than a stranger). Don't buy into the idea that her money should be saved for her and your siblings' inheritance.
Protecting yourself from ever-increasing demands is not easy. It's good you see this coming in advance so you can take steps to guard yourself against it.
Or for groceries, there are on-line services where you order groceries and the groceries are delivered directly to your Mom's door... but usually there is a minimum amount you can order, and a delivery fee.
I wound up being my parents "driver" and they want to go 2 or 3 times a day somewhere. I couldn't do that since I was working, so I usually had to take a half day off for appointments, and weekends for groceries and other errands. Mom would want to go to 3 different grocery stores because each one had a special sale on something. I was in my late 60's so this became very tiring. I did get them on the on-line grocery service which was a godsend for me.
Ok, you are asking your question early enough so that you could set boundaries. When Mom calls for you to drive her, tell her "sorry, I can't possibly do that". Make it one day a week, and let her use the community transportation the other days with the other gals in the complex. Surely it would be more fun.
"Mom, I can give you one afternoon a week for errands and doctors appointments. If you need to go other places, here is the number for the senior bus and here is one for the local can service. They can get you anywhere you need to go".