Everyone knows that supermarket shopping when you're hungry is bad news: you come back with twice as much food as you need, most likely including the more expensive 'treats' you'd normally consider out of bounds, and it never ends well.

But what about other, less obvious factors that might cause you to spend more than you need? When else should you lock up your credit card and avoid going within a mile of any shops? Follow the jump for five examples of when we're at are weakest and most vulnerable to temptation -- and my tips on how to avoid it!

1. When you've had a drink

Until quite recently, it was very difficult to go on a spending spree while drunk, unless you happened to be intoxicated between the hours of 9 and 5 on a weekday, that is. But thanks to the wonders of online shopping, later opening hours and the ever-expanding boundaries of the shopping mall, this is sadly no longer the case.

Alcohol can give us all sorts of delusions about ourselves. We feel more attractive, more confident and more decisive. And to many people, this feeling of invulnerability also extends to feeling rich. So if you're in the habit of pouring a glass of wine while browsing for shoes, clothing or games consoles - don't be surprised if you've hit the 'purchase now' button a few more times than you might have intended once you get to your third. You are also far less likely to exercise caution when making a purchase while drunk, so it's no wonder it can lead to all manner of spectacular mis-buys - beer goggles can definitely apply to goods as well as people!

The solution? Don't go near any shopping sites if you're likely to have more than the smallest amount of alcohol in your system, and when you're out in town, steer clear of shops that stay open late to lure in a more lubricated type of customer. I've found that stores selling music and DVDs are the most likely to be guilty of this! Also, be wary of how this effect can impact on your bill if you're dining out.

2. At the last minute

Nobody enjoys shopping in a panic, and it's often the frenzied, last-minute sprees that work out the most expensive. If you need to buy something specific - a dress for a wedding, say, or a birthday present - but haven't left enough time, you'll have difficulty making an informed decision and unless you stumble on a lucky find, you'll probably be unsatisfied with what you end up purchasing. In the worst cases, you'll buy one item in a panic, only to find a better example later on and fetch up spending twice.

So try and plan ahead whenever you know you have a major purchase to make. This will make the whole experience far less stressful, and will ultimately result in getting more for your money. If it's too late for that, either try and work with what you already have -- can you combine clothes hidden in the back of your wardrobe to make a new outfit, or re-gift any presents you don't want?

3. When you've just been paid

It may seem counter-intuitive to advise abstinence when you're at your most flush, but it's very easy to fall for the illusion of being better off than you really are at the beginning of the month -- just after receiving your paycheque and before your rent or mortgage payments and bills have left your account. I know that this tends to be the most expensive part of the month for me, and I'm often shocked at how much it impacts on my bank balance later on. It's often hard to predict at this stage what else will come up during the month, so even if you think you can afford something, it's possible you'll regret it two weeks down the line.

Tempting though it is to spend to your heart's content when the numbers look good, it's far better to wait till the end of the month and have a more realistic idea of how much you have at your disposal. That way you're in for far fewer nasty shocks, and will know exactly how much you can afford to spend.

4. When you're madly in love

When we're in the first flush of romance, we all tend to lose our grip on reality to a certain extent and that includes all those annoying and inconvenient things like money. Why, after all, would you want to think about budgeting when your mind is on flowers, chocolates and living happily ever after with the love of your life? You'll also be wanting to look your absolute best for your sweetheart, so that means new clothes, new hair, new shoes and ideally a makeover for your home.

5. When you 'need cheering up'

Conversely, when you're feeling low, an almighty 'retail therapy' session can seem very appealing. Bringing new and pretty things into your life can feel like a quick fix to mend your woes and for some people it's the very 'buzz' of spending when they shouldn't be that can provide an attractive escape route from feelings of depression.

There are two ways to approach this problem: firstly, keep a close eye on your finances so you know the impact that out-of-control spending has on your mood in the long-run. Secondly, make a list of things that cheer you up that don't involve spending lots of money, and devote more time to pursuing them instead.