What I carry in it is:-

• sleeping bag (YHA Plume 2lb 13oz mountain bag, now over 40 years old)
• old fashioned over-your-head canvas anorak
• cagoule & waterproof overtrousers
• spare gym trousers for walking
• thick wooly jumper
• decent slacks for hotel use
• 2 decent shirts ditto
• plimsolls ditto
• pair of socks & underpants (I wash them as I go along)
• spare walking shirt
• ski gloves
• YHA wooly balaclava hat
• 2 x 1 litre plastic water bottles, full to start with
• dried fruit or sultanas for lunches
• Kendal mint cake (®Wilsons)
• emergency small tin of corned beef
• sponge bag with:-
  • toothbrush & paste
  • soap (2 small hotel pieces, in case I lose one, easy to do in a hut)
  • flannel
  • footrot cream (Mycota)
  • Savlon (®ICI, antiseptic cream)
  • sun cream
  • sun lipstick
  • hairbrush
  • nail file
  • 'housewife'
  • very tough scissors
  • sticking plaster strip
• old-vitamin-pill-tube of detergent (as I wash clothes as I go along)
• camera
• camera battery charger
• maps, compass & whistle
• paperback for evening reading
• tiny waterproof diary & pen
• (usually) day sack

On the outside is an ice axe, sometimes (as in 2001) crampons & a light ladies brolly, usually used as a parasol but occasionally as a brolly.

For a day sack, I use a cheap Swiss tote bag with a couple of strings, so it can be carried as a rucksack. This is about 5 litres. It only has to carry a water bottle, camera, map, compass & lunch. This is very small: nothing like someone's suggested 25-40 litres.

Note...that, no matter how beautiful the weather may appear to have settled to,
I am prepared to meet a sudden blizzard. A cloudless day in the Alps can change its mind!