Things you just can't economise on

What with the economy being as it is, probably most of us try and save dosh by avoiding common consumer pitfall like using price as an indicator of quality or being a slave to brands, especially with stuff you buy all the time. So, for example, I reckon Sainsbury's own brand vodka is not as good as Russian Standard or Absolut but is both cheaper and vastly superior to that best-selling brand of paint-stripper known as Smirnoff. And I take the view that Calvin Klein underwear is both literally and metaphorically pants. You might not agree with these examples but you know the sort of thing I mean.

But I was wondering if there's anything people have found that it is impossible to economise on? I don't mean things that you can find cheaper or discounted if you root around enough - this could apply to any product. And I don't just mean things that may be a false economy in the long run but function properly. Cheaper washing up liquid might not last as long as Fairy but it cleans your dishes perfectly well. Rather, was thinking of things that just don't do the goddamn job? I reckon you get what you pay for with the following:

Razors. Cheap razors give you a shave that's a little too close, don'tcha find? You want to avoid turning up with bits of bogroll stuck to your face? You need to pay for it. Speaking of which...

Bogroll. Half the price but you need to use four times as much with nasty cheap abrasive bogroll. It's just not worth the suffering.

Guitar strings. More expensive ones last longer but sound better than cheapo ones even when they're freshly on. Knew this guy who had fabulous guitars. He had fabulous guitars because he had plenty of money - but said he would never pay more than a fiver for strings? Lost his damn mind if you ask me. I'm a strong believer in the power of strings. Want your guitar to sound good? Put some decent goddamn strings on it then.

Ciggies. Mayfair? Blech! You might as well give up. Although I guess we all should...

Jewellery. My girlfriend's suggestion. I wouldn't know but won't be challenging her view by trying to smuggle some Gerald Ratner shit past her.

Anyone disagree or have suggestions of their own? Would welcome contributions if this stupid comments system allows.