Mine are:
Don’t buy takeaways. That’s easily £30 down the pan for one meal. So expensive. We get a Sainsbury’s ready meal for that evening where we would otherwise be tempted.
I meal plan, and cook from scratch with fresh ingredients, pasta, eggs, rice, vegetables, potatoes etc. I cook double portions in one go so I just stash meal 2 in the fridge & with 3 meals planned that’s easily a weeks’ dinners sorted. I’m vegetarian, meat is so expensive. This weeks food shop came to £36 - that’s for a family of four. I’ve batch-cooked special fried rice, paneer (with butter curry sauce), macaroni cheese, and vegetarian meatballs. Each of those 3 dinners will count for two nights, and tonight we’ve had jacket potatoes with cheese & salad - cheap as chips.
An excel spreadsheet of your family incomings and outgoings is your friend. I track all bills, I know exactly how much comes in & goes out each month, how much I’ve got left to play with. I am strict with money too - I don’t waste money on expensive purchases or whims. If I have money to spend it goes on experiences - days out or holidays (mostly UK holidays.)
Baths - the kids are washed in the same bath together. I don’t bathe/shower every day, maybe twice a week. I wash myself with a warm soapy flannel in the areas that need it. It’s really not necessary to bathe/shower every day - it’s a modern indulgence & your body doesn’t mind being naturally left alone for a few days in between washes.
Heating on at night & off in the day. No need for heating in the day if you get out & active. People get cold if they stay in & don’t move around enough. Make sure we always have layers on. Lots of them.