Ok, I realise now that I may have gone overboard with my children but as Ds1 is in year 11 and super organised it clearly worked.
2 pencil cases, both live in the school bag and are never taken out at home. In one case, pens, pencil (mechanical no sharpening required) glue stick etc, the other has protractor, coloured pencils, compass etc so the less used items. Also spare coloured pens which are part of their required equipment. If they don't have this they get a negative in their planner so they are prepared.
Rucksack is a laptop bag as they are padded against their backs and can take a lot of weight.
At home, wooden magazine file for each day of the week. Bag emptied from the day books put into correct day file for when it is next needed. Homework written down and put on noticeboard (see below.)
Timetable, copied, pinned onto noticeboard in room, opposite where they sit at the breakfast bar in kitchen and on the back of the front door.
Noticeboard in room - a section divided into days so they can pin up homework using ready cut strip of paper so they can see at a glance how much homework they have and when it is due in. Noticeboard was from Ikea, I just put coloured paper on it which I draw on the days of the week.
Weather app on phone so they can see if they are wearing their waterproof coat to school or not.
A4 plastic wallet to bring home letters from school, although planner is marked when staff send letter home.