I totally get it! Especially the "tightly sprung part."

I feel the same way about not wanting to change my mattress. We had a few potty-training mishaps with the kids, and I’d scrub it clean with every solution under the sun: online and offline! So many memories. Plus, over time, it’s become so comfortable, like a memory mattress in its own way. Hehe

So yes, I really understand you!