I work 3 full days. Working half days is not doable in my job because I will never get to leave on time.
I work 4 hours one day then 6 hours then 4 then 6 then 4, worked it out because I still get paid more but I'm not missing out on the important days so I won't fall behind (books get closed on a Thursday so 6 hour shift) depends how many hours you do but my work offers flexible working so we're figuring it out as we go if I have to change shifts I can
I work 3 days and 9 hours a day. My commute takes 45mins - 1 hour so doing short days just didn't make sense. It works really well for us as I do nursery drop off and my husband picks up. We managed to find a nursery with long opening hours so this is something to consider too if you're going down that route for childcare.
It depends a bit on your job and commute. If it's a long commute then you're having considerably more time away from family by doing 5 short days as you do the same journey 10 times not 6. My job becomes slightly more stressful with a shorter day. However if I'm pumping and I need to do 2 days in a row I can't do a full shift, I need to leave at least 1 hour earlier to have enough time to sort myself out in the evening before bedtime including Sterilising pump and freezing ice blocks for the next day etc. From your perspective especially with pumping it's nice to have a day at home in between work days to rest and sort everything out. But if baby is going to nursery or someone else's house it's better for baby to do 2 days in a row there to get used to the environment as they forget quickly. From that perspective 5 short days may be better for baby for nursery as they get more of a routine.