3. Important and urgent stuff for the kids
4. Unavoidable transport costs.
You might need to add one or two things to the list but keep it as short as possible.
Once you have your list stick it up on the wall or fridge and get yourself and envelope (or jar, or virtual pot) and for one whole month every time you want to purchase anything not on the list put the money in the envelope and write what it was you were going to buy down too.
At the end of the month review the list, ask yourself do you really need the things that you have on the list. If you still really need it buy it, if you don't really need it leave it and put the money into your savings account. You would be surprised about what you decide you really need.
One month I spent about £20 in the whole month and put the rest towards a mortgage overpayment. Do this a couple of times a year and you would be suprised how little you really 'need' and how much you save.