I've got a running post about the fact I'm pretty much having a nervous breakdown - lots of answers on there will help you understand why we go part time.
In a nutshell, I had a stressful career. I was full time until eldest was 8 and youngest was 3. We both were full time. Over the years, eldest was diagnosed with various issues that were not apparent really until around age 6. Crunch time came when we were told both children needed weekly ongoing therapy that will take years. The appointments are during the week only and an hours drive away. Neither of our work would let us do this. So that was the first reason for part time.
We then also realised that both our kids having to do breakfast club, after school club or be picked up by a childminder was also adding to everybody's stress levels. Kids were knackered, I'm sure most kids would be but when you add in that they have additional needs, they were really suffering. Again - our work is not flexible on working hours.
So, stress from children being tired and overwhelmed due to long days and childcare, then stress for us at managing that stress. Late dinners, early get ups. It made us so miserable.
The appointments for therapy were the catalyst for us deciding we couldn't live like it anymore.
I have friends who have adopted and they are both still full time. However, they work in the same place that their children go so no childcare. They also are able to work from home one day a week which alleviates some of it. They are struggling.
Although times are hard right now, me going part time was absolutely worth it. They now have 3 days a week where they can relax and not be rushed around in the morning. They have a short day and dinner early.
The only reason we can afford to do this is because both children get DLA.