Maire-aine - do you turn your mattress regularly? Some can get 'accustomed to your shape' to paraphrase a song from 'My Fair Lady'... and they stop providing adequate support.

You can rotate it along any axis, just so long as you do it regularly, say, every 6 months or so.

I have so many things to do and so little enthusiasm to do it today. So I've elected to have a 'TV' day, and in about an hour, I have to take Limpit to her piano lesson.

LTS