Do you have to have brake pads replaced if you replace discs?

Also how much do brake discs cost also? (UK)

Ford Fiesta Studio

You are asking if the pads should be replaced if your are replacing the ROTORS. The answer is they SHOULD be replaced to get you back to an optimal factory brake situation. The PADS are DIRT CHEAP compared to the ROTOR and the LABOR required to swap them in. The pads can wear out long before the rotor. The rotors can also be "turned" to remove a layer or situation of "uneveness"… And the pads are easy to replace.

A better question, why would you even think of replacing the rotors (or discs for what that means) without replacing the brake pads. But I question what you really mean by disce.

Yes, it's a good idea to do both at the same time.

Yes its sensible to replace them both… The disc are not too dear… Unless you buy them from ford… You can buy a pair circa £40

Why wouldn't you? By the time you've taken everything apart to replace the discs it's only a small extra cost to replace the pads, then your brakes are good for a year at least.

If the discs need replacing they will be warped or grooved and the pads will have compensated for this. When you put them back on with new discs chances are they won't be parallel with the disc surface and so not work as well as they should. So new pads always, they are quite cheap compared with the discs and you shouldn't be charged any extra labour because they would be removed anyway.
On the other hand, if you just require new pads you shouldn't normally need to replace the discs. Audi insist new discs should be fitted when changing pads but that just seems like blatant profiteering.

Yes - simple as that. Crazy not to.

Yes. The pads will be the contour of the old rotors.
The rotors are not expensive.
Any garage will quote.

I wouldn't even think about it unless they were in like new condition with very little wear.

Why not, since you're already in that deep on the job. If there's lots of meat left on the pads and you need to keep the cost down, you can reuse the same pads. Here in the US, I've been paying about $25 each for new brake disks and replacing two rotors takes me about 1/2 hour.