To expect the same childcare as your SIL is receiving

No one owes you free childcare. period.

PIL made it crystal clear to all their sons that they were happy to babysit and help out but were absolutely not willing to provide regular childcare for work. They didn’t agree with working Mums. It annoyed all us DILs as none of us had plans to ask them anyway.
SIL was the last to have DC and funnily enough they changed their tune because it’s ‘different for SIL’. They actually said to my eldest they were more excited to be grandparents for SIL’s children because she was their daughter. This amongst other things really changed what was previously a good relationship with PIL.
Things are changing a bit now SIL’s DC are a bit older but it still rankles.

On the flip side with adult DC I’m terrified about becoming a grandparent and being asked to provide childcare!

I completely agree @Globules. The crazy thing with our version of this is my PIL do love my child, me and my husband. I don't think they realise at all how upsetting their treatment of us has been. I swear the feeling I had towards them quietly died when they didn't visit my baby in hospital for days but fussed around an older well grandchild, genuinely couldn't believe it. You reap what you sow and the grandparents on here talking about entitled behaviour and they can do what suits them are delusional.

I think what you're feeling is the lack of your own parents OP. Normally you would turn to your own mother for the support that the PIL are giving their daughter and for whatever reason you can't. The unfairness is not that they don't provide equal childcare for you and your SIL, but that you don't have your own parents to call on.

It's sad, but you can't really expect the PIL to fill that gap. They don't owe you what your own parents don't provide and it's not fair to expect it of them.

So did he over promise that living super close to them would mean help from them, but failed to actually have that conversation with his parents?

Because if so, you were clearly manipulated by your husband and have every reason to be a bit irritated.

Did he say whatever was required to get you to move close by?

Well, it's big of you to allow them that(!)

To answer your question, the correct amount of support to 'expect' is none. I get what you're saying re the inequality and that's not ideal, but what stands out for me is that you keep using the word 'expect' and failing to acknowledge that they are doing you a favour. You sound breathtakingly entitled and ungrateful.

XH and I had 2 kids first. No offer of any childcare, but ILs were working full time. We asked for the odd weekend overnight about twice a year. ILs made little attempt to initiate contact, it was on us to be proactive and see them.

When my kids were 4/2, SIL had a baby. MIL dropped 2 days at work to "help out and get to know my grandchild". Not 1 day to each family, but both days to SIL.

SIL household earning more, less stressful jobs, less time intense jobs.

XH always felt loved, but knew his sister was the golden child. He never spoke to MIL about how she made him feel with that decision.

My children have a very very poor relationship with their grandparents now. They last saw them in 2022 when they were teens. My children are ambivalent whenever I mention their names.

XILs taught me an awful lot about how to not parent and grandparent.

You're not wrong to expect parents to allocate fair amounts of time to each of their children OP.

Honestly not saying this to score points but why can't time spent with grandchildren be evaluated when there are more to consider? It from the outside does feel a bit mean. I have never asked for any meaningful childcare and its just a way of spending time together or giving me a little break. I do think there are long term relationship consequences to prioritising one set of children. Maybe downscale both if it is a bit much?

This OP could have been me writing this over 10 years ago.

I hear you OP! I am married to the brother. Own parents not in picture. Massive divide in childcare from the grandparents.

feel free to drop me a message if you would like a chat!

Wouldn't they want to help their son? Have a deep relationship with his children.

We never lived near either Grandmother(both Grandfather's died before grandchildren were born) so never expected childcare from Grandmothers. Yet, they were involved with our children even though they lived hundreds of miles away.

I would hate to think that I would favour relationship with any Grandchild over another.
I helped both Mothers as they got older. Making sure my brother who lived nearer to my Mum got a break.I helped my MIL as much as possible as her daughter lived overseas.
We made sure we visited both of them as much as possible( they lived 200 miles apart).

I think daughter always gets preference. I’ve seen it before with friends and my dsis is currently experiencing this to the point that mil was recently asked to babysit weeks in advance, had put it in her calendar, and mil then called and cancelled on the day because her daughter needed her more

Mm I think it's often a case of getting in first. I totally can see why someone would mind a toddler for a few while and then not want to add in a new baby on top of same toddler. To be strictly fair you'd need to drop toddler and mind baby for exact same period if you weren't up for minding two smallies at the same time which lots of people aren't especially as they get older or else add on extra days which is hard too.

If I've committed to say, three days a week to one child because there were no other children, then I've committed to three days.

If I can help on the other two then I will but it shouldn't be expected

Only my son has had children so far.

should we refuse to mind them cause my partner will be god knows how old before his daughter has kids coz she’s 15 right now and he’s 64?

Of course they are but they should love their children and their grandchildren equally. It isn’t hard to plan how you plan to be equitable to all your children ahead of time knowing they might not have GC at the same time and knowing you might be less inclined years down the line.

Your parents being older now is definitely a valid consideration.

But surely this isn't about your SIL? Yes your SIL has her own mother, but is her DH not your mother's son? Wouldn't your mum want to help her own son and treat her children and DGCs equally?

The number of people focusing on the OP's relationship with her MIL is truly baffling. It's nothing to do with in-law relationships. It's about treating your own children equally, and your own grandchildren equally.

I get less help than my sister did for her kids (my parents had sister's kids 4/5 days and nights a week until they started school).

From my perspective I didn't expect any help. My parents helped a few days a week with my eldest but will not be doing any childcare for youngest. No falling out, they just have less energy than they used to and I'd rather they do nice things for themselves. Yes it will be expensive for me (I live in central London) but they don't owe me anything.

When are grandparents allowed to have their own life?

They are more than childcare you would hope

You sound as though you’re more pissed off about not getting the same amiunt of childminding from them, rather than the same amount of time/attention

My SIL is married to my brother and there is no way my parents will have their children as much as they see mine.

My SIL is a twat for one so my mum isn’t going to go out of her way to support her, especially as she has her own mum, and my parents are now 8 years older than they were with mine!

Okay. But can you see what I mean about the GP’s getting older? Say they looked after SIL’s DC full time 5 years ago. Now they’re older, can they still offer the same? Is it fair to ask? You say your DH “over promised” - so really your beef is with him rather than it being unfair?

Yes ideally they should provide the same for each, but it's hard to cut down on existing help that is an established routine maybe, in order to provide for the "newer" kids, and not get overwhelmed.
You can't really expect anything, but it is annoying to be treated differently. Sadly one set of GCs often get more than another. Some parents are very grabby of GPs time and make it hard for them to say no. I had far less help than my sibling with childcare, as she was a master manipulator and my mum felt she couldn't say no, then there was nothing left for me/ my kids. If I asked I'd be guilt tripped.
The favouritism massively affected the relationship. But we are much more self sufficient as a result, compared to sibling's family who still have my mum running round after them. So try not to be resentful if you can. It can be good to be less enmeshed with GPs and do your own thing.