Our memory foam mattress is about 5 years old now, possibly older, and hasn't sculpted either of us in it. It goes back to normal shape within seconds, just retains the heat in that spot which makes it 'sculpt' to your body more quickly than when cold

Ours has a 10 year guarantee, so fairly confident in it for a while longer

and it didn't cost that much, other mattresses of the same spec & size were double the price so we got a brilliant deal with it imo
^^ Going point about the noise too, I forgot how noisy normal mattresses were