In reply to talon_guy:
A few winter tips...
Take a 500ml flask of hot ribenna instead of water.
Carry the cup from the flask in your pocket on the walk in and use it scoop water out of streams.
Eat and drink lots in the morning and evenings.
A big bag of haribo is good.
Take savory food as well as well as sweet stuff. Scotch eggs and pork pies are good.
Whilst bothy bags and belay jackets are great climbing with a virtually empty sack is better if you are trying to push your grade.
To get away with out a belay jacket I wear lots of clothes.
Normally on the walk in I wear a merino top and a hooded windproof top.
When I get the climb I'll add a R1 Hoody, a lightweight sythethic pullover and waterproof shell. If it is really cold I might as sythethic vest too.
If I can help it all that will be in my sack on the route is:
Mitts
Map Compass
guide book
very minimal First Aid kit
Food
Small flask
Headtorch
I can normally get every thing I need into a 30 litre bag, unless I am climbing with my girl friend, when I'll carry both ropes and the heavy part of the rack.
HTH
NEVER EVER leave your headtorch in the sack at the bottom of routes!