How do I protect my life now that I am retired and my mom is becoming more dependent?

Dorianne has a great approach for setting boundaries. Your mother does not need your entire schedule. Give her your AVAILABILITY schedule. You are an adult. You don't need to tell Mommy all your plans! :)

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 feel like I am the wrong person to answer this, given the role I'm now taking in my mom's life. BUT....as an introvert, I've gotten really good with OTHER people over the years (acquaintances, friends, employers) at giving them my AVAILABILITY schedule. Which is different than my whole schedule. Like....for example I perform music with a band occasionally. Ok, that takes a lot out of me, not just physically, but also mentally and emotionally. So I need that whole day to mentally psych myself up for it, and another day away from literally everything except self-care the next day, and I need a whole day sometime beforehand to practice as well. So all 3 of those days are OFF my availability schedule. (Edit: this doesn't always work so great with employers, but I try to plan ahead with what gigs I will take or not take, which are usually on the weekend anyway.)  I have always had a rule of taking one day a week off from humanity, meaning I interact with zero people that day. So that day comes OFF my availability schedule, as well. Et cetera.  It's surprising how well it works. Very few people poke their noses deeper than that.

You set boundaries.

"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".

Mountaingirlash, ask at the community front office if transportation is available for the residents to go grocery shopping or to appointments? Usually such places have a mini bus service, either free or a minimal charge.

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.

Do what my sister does (rather than what I do). Fill up your schedule and don't deviate from it unless it's an absolute emergency. Schedule vacations, dinners out, excursions with friends, weekends away, community events, etc. My sister does that and as a result, my mother never calls on her because she's always busy.

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.