Keep in mind that you can't spend all your income in any given month in that month. You need to put money by for annual and irregular expenses like Christmas, holidays, school uniforms, broken pets, cars or appliances as you will need to spend on these sooner or later. Non essential spending comes after these items.
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Be aware of how small purchases add up to significant amounts. Food and drink outside the home is a good example. Many people buy lunch and coffee while at work, but £5-10 a day can add up to hundreds of pounds a month or thousands of pounds a year. Fine if you can afford it, but a good place to cut back if you find yourself short of money for other things.
As in divvy everything up. Bills in one pot, extra expenses (school trips, birthdays etc) another, weekly shopping another, clothing budget.... and always have a savings pot. I zero off my account each month and the day before payday anything left is put into savings.
I'm with Bumpowder. Another good tip is MEAL PLAN. I food shop every Friday morning and on a Thursday, I'll create a food plan with the help of my husband. I look at each meal and go through the cupboards/fridge/freezer to check whether we already have ingredients in or need to buy them. If you do this, you'll also cut back on waste. If I get any free time, I check the cost of the shop online and shop around... love Aldi. I spend no more than £220 a month on food. I sometimes split that into however many Friday's there are in a month (on one pay day) so this month it's £55 a week and if I only spend say £38 one week, the extra money will either stay in the 'food shop' pot for an extra bottle of wine or something or go into savings!
Write down incomings. Write down outgoings. Leave enough money in the bank to cover those. Once done, move some to a savings pot then allocate yourself money to spend each week. Withdraw this from the bank each Friday, you can only spend what's in your purse. Anything left on the following Friday, tip into a jar at home. Leave the jar until it's full.
Carrying the cash makes you think a bit more about spending rather than just handing over a card.
I also save for my make up and skincare. My cleanser costs £60 ish but I last got it in January and the bottle has nearly finished but I put £5 a month into an envelope to cover all this as I know how much it costs and how long it lasts.