How do you handle friends who always need last minute favours?

[NourWu]

A friend keeps asking me for last minute help and it is starting to feel like I am her default option. School pick ups with an hour’s notice, watching her toddler, giving her lifts when she forgets to plan ahead. I have my own DC and a full time job, so it is getting harder to drop everything every time she messages.
She has a partner and family nearby, so I am not sure why it always ends up falling on me. I want to stay supportive but I am beginning to feel taken for granted.
AIBU to think I need to start setting some boundaries before this becomes a habit?

just don’t answer/ leave on unread.

Sorry but I can’t help you today

Say no if it doesn’t suit you. Lots of different ways to phrase it “sorry that doesn’t work for me, hope you get something sorted” “sorry I have plans” “oh if only you’d asked me earlier sorry no can do”.

Ypu could also go with “oh I was just about to call you and ask you to do that for me”. Or just don’t answer your phone when it’s her

She’s only trying you because her family and partner say no. Follow their example.

Just say no, sorry I can't. The more you accommodate it, the more she'll ask!

by text (or WhatsApp etc) - ignore.
By phone? practice saying "sorry, no can do"
In parson? see above.

You start by making yourself less available, of course.

It has already become a habit. You are allowed to say no. Her partner obviously does.

"So sorry just saw this. Had a full on day! Hope you found someone to help!"

Start asking her to help you. She might actually really really need it. But if it doesn't become reciprocated that's it. Eg I am at the end of my tether and about to collapse. I'm asking favours here there and everywhere. I'm remembering who helps and in a few weeks when it's easier I will take their kids out and give them a break. I don't even know some of these people but I'll remember who has helped to pick me up.

Thanks, I probably just made it too easy by saying yes too often.
I’ll start being more direct when it doesn’t work for me. If she still keeps pushing after that, then I’ll know it’s a bigger issue.

Just say no.