I would leave it, too. Once you're at work I'd imagine you don't notice the extra time as much as you'd feel having to get ready/commute/come home routine on the extra day.

Plus, it is likely that you will end up getting stuck at work later than planned on days when you go in and don't have a hard deadline to get home

-bdtd mom who has worked PT

I'd leave it.

What does the nanny do with no children in the mornings? Would they be open to working on Friday?

I'd leave it as is. If your nanny cannot work Friday, you're going to work a couple hours and have to leave. That would only marginally shorten the other 4 days of the week. I'd rather just have a 3 day weekend.

I need to work 35 hours per week but I can pick the hours. Lately I have been doing 7:30-4:00, 4 days per week. This works pretty well because th commute at those hours is only 25 minutes. But now that all of my kids go to school, I was thinking of spreading it over 5 days?
Kids are 4, 10, 12, 13.
I have a tnanny who works 7-5 on the four days I work.
DH works a lot and does school drop off one time per week.
The four year old only goes to school 8;30-11;30