Eat less processed foods, buy more fruits and veg.; as students we used to haunt the market stalls for 'odds and sods', boxes of stuff that was going to the tip. Said it was for our chickens
Turn up sauce/ketchup/squeezy bottles to drain into the lid. I get another 2 weeks at least from squeezies. Dad used to add a little vinegar to sauce/ketchup, give it a good shake and hey presto! another week of use. Also toothpaste: turn up the bottom and press the paste gently to the top. I've had 6 weeks more use out of my sensodyne tube
. If necessary put a peg on the bottom to remind yourself to squeeze gently.
Scrub veg rather than peel: the skin is where the vitamins are after all. Any left over chips - keep in the fridge overnight to cook in the frying pan with a little olive oil for supper ;-). they crisps up lovely they does