New sofa seat cushions/restuffing

[mouselittle]

has anyone replaced their sofa cushions? I don't want to buy a new sofa when replacing the seat cushions would make it like new.
has anyone done this and can advise on cost and where to have it done? would it be an upholsterer? not keen on buying online.

We had feather sofa cushions replaced with sponge cushions. Didn't replace the cushion covers - just the stuffing - as the feathers were heavy and just flattened as soon as you sat on it and made the sofa look a mess - the foam just bounces back into place! Also had a sofa recovered. We used an upholsterer - and he came round and measured etc.

Thanks. This sounds exactly what I'm after. could you give me an idea what you paid per seat cushion or altogether for the foam padding? is it very expensive?