Is it worth doing work to a house you plan to sell?

Make it clean, tidy, and clutter-free.

Old kitchens have never put me off, but a living room where I couldn't see the walls for pictures of elephants and there was dirty washing piled up in the bath certainly did... True story.

I would far rather buy a house with an elderly kitchen than one where the kitchen was brand new but not to my taste.

And first impressions count, so go and stand on the pavement outside your house and have a think if there's anything quick and cheap that you can do to improve your kerb appeal - sweep the path, cut back the bushes, even give the front door a good wash.

Save your money for your new home.

I think it depends a bit on the price of the house, who your target buyers are, and how tired / scruffy the place looks.

If the decor is really tired or scruffy then it does make the whole place look uncared for, and as a potential buyer I would be wary as to whether that meant that maintenance had also been neglected, so a lick of paint can make the place look much better cared for at relatively low cost. (It also allows you to make it more neutral so people can more easily imagine their own style)

I would not put in a new kitchen as tastes vary such a lot. When I was viewing houses last, I did look at a few where 'recently re-fitted kitchen' was listed as a selling point, and the price reflected this, and with almost all of them my reaction was 'the kitchen is horrible and I'll need to budget to re-do it when I move in', and with the ones where I liked the kitchen, it was 'it's nice, but not nice enough to justify the price difference'

Which of course is a personal reaction but I think you're as likely to have that reaction as a 'great, gorgeous kitchen' one from people, so you'd probably be better leaving it as is.

Carpets I would hire a carpet cleaner but unless they are really dated or in very poor condition wouldn't replace them.

I'd definitely do the basics as others have recommended, but so long as the bathroom and kitchen are functional I probably wouldn't bother.
we bought a flat that needed a new kitchen and bathroom (no oven in kitchen, strange set up in bathroom) and have saved up and done these and as soon as possible, we hope to sell next year and to have made money as feel the work involved in the property probably put people off. However the disruption of getting a new bathroom/kitchen in is not to underestimated. Unless they are not functional I would leave them and allow a new buyer to put their own stamp not the place.
May be worth getting a few local EA around to give you some ideas? We have three around for quote after having done the bathroom, as I didn't want to do the kitchen (felt it would be wasted money) but my husband did. All three recommended we invest in getting kitchen done as said the lack of functionality would put buyers off.