I would like to preface this with I KNOW she's doing us the favor... and daycare is expensive...

That being said, she calls off a lot. When she moved into our area she approached us and offered to watch our daughter free of charge up to 3 days a week while we work. We did not ask her. So the way it worked out is during the day my daughter is in daycare 2x a week, with my MIL 2x a week, with my husband 1 weekday and then with me on weekends. My husband and I both work full time and with the cost of daycare this has been extremely helpful. That being said my MIL has been "calling off" about 1x a month. She usually gives me about an hours notice... which Im not usually looking at my phone because Im getting myself and my daughter ready for the day. It's stressful because now I either have to call off and use my vacation time (ironically earn 1 day a month) or scramble for last minute care. My husband is already at work when she notifies me and would lose pay because he does not accrue pto. On top of that I'm 17 weeks pregnant and need to use my time for maternity leave - so I'm really trying to be judicious with it. I want time with the baby when he comes. And it just doesn't look good to call off every month at my job. Even if I wasn't pregnant i dont think its right that all my vacation time is being alloted to his mother calling off. I work hard for that time and want to be able to use it how I see fit. I don't want to sound ungrateful but I feel like it needs to be addressed. I understand people get sick and things happen, but i feel like 1x a month is too much. If it's too much for her then please tell me so we can make other arrangements. Is that rude to say? There have also been times that she requests to switch days (for appointments or travel or whatever) and we have always accommodated her without hesitation. Am I being a brat or unreasonable? I mean... we're working. We're not at the club or doing date nights or anything "extra".