Since having DCs, I've worked p/t, f/t and am now a SAHM to school age children.
SAHM to school age children generates far more mess. When I worked f/t, there was no breakfast in the house, there was no lunch in the house, there was no tea in the house, only dinner because most meals were covered by nursery/ wrap around care.
The DCs do more activities so that's more changes of clothing. I don't wash after every wear, but it's more sets of kit to need washing at some point. I get more running done, so change more often. I wear more layers in the house to keep warm than I did with my work wear, again that increases washing.
The DCs spend more time in the house to mess it up. More dust from spending time in the house. More ins and outs to walk dirt in from outside.
When working, shopping was done on a Friday evening straight after work/ pick-up and we went to the supermarket cafe for tea then around the shop which was fairly efficient at a quiet time. It takes longer doing it in the school day when it's busier.
I now volunteer in school 3x half days a week which is a significant chunk out of my avaliable time. If I'm in long run season for a HM, that's another good chunk of a day gone.
I'm still catching up on non-essential decorating and decluttering that was just paused when I was working and the DCs were young.
The 6 hours that the DCs are in school disappears very quickly. Admittedly I'm not the most efficient of people and do a fair bit of MNing in the face of exciting activities like folding washing. I'm not sure how I fitted in a 60+ hour job before, but I know why I'm not still trying to combine it with family life! (And we are all much happier for being more relaxed with time and being together at home more).