It’s fine to have boundaries OP.
Mil and Fil are both still with us but a plane ride away. They can be demanding and controlling. Over time I’ve come to figure out what boundaries work for us (and me) and have educated DH to grasp that ‘active management’ is the way forward.
Eg. I have a five night maximum of visits either way. Ideally I agree shorter stays of 3ish nights would be better but to make the journey worth it, 5 is manageable.
The few times we’ve done longer tempers fray and there’s a row.
10 night over Xmas sound too long to me, but a kind thing to do the first year she’s on her own. It will probably feel too long and I’d make sure I found and took opportunités to discuss that with her and DH and start to put in place that next time it will be shorter. Once you’ve found that natural limit, stick to it.
Eg PIL don’t come for all of half term. They’ll arrive on a Wednesday and leave the Monday the kids go back to school.
We also now sometimes book them a small apartment just around the corner from our home for some
Or all of the visit. Our place isn’t huge and though they come here for breakfast and leave we’ll after dinner it helps them and us to have privacy and space at the beginning and end of the day.
I’d also rethink she has to only or always come in the school holidays. Else that may become her expectation every school holiday. Having her during term time is a way to make her visits less high impact. And she might well enjoy the white time during the day while you’re all our at work / school (unless you don’t work or work from home!).
Christmas id establish a rota similar to whatever you had before. Is your DH and only child? If so I’d probably accept she’ll always be with us, but do one year hosting her (or visiting her) and one year with your family taking her along. Again, I’d keep that short, maybe sending her home with your DH on 26th or 27th while you stay on with your family for a couple more days etc.
Kind but firm. Push back if she over steps.
PiL insisted on visiting the first school and bank holiday after I’d returned to work following Dc2 (I’d asked for later. It they had other holidays booked). I said ok, I’d it had to be then, could they please arrive in time to help one day we had a childcare issue, and leave in time
To give us one or two days of family time before work & school resumed. They did neither. I was very pissed off and avoided them during their stay. So much so they commented to DH and I reminded him why. They can be selfish and impose and make my life harder if they want but then I’ve not got it in me to be entertaining them.
It hasn’t happened again.