I've always had the same one. It's older than me, but I sleep like a baby on it.
Funny you should ask. I just had one delivered, not 30 minutes ago! A good mattress is important because, as you said, we spend a good portion of our lives sleeping,and since I don't want to wake up feeling like I've been hit by a truck, I always get the best one that I can afford (and suits my needs).
The last one was custom-made for me about 20 years ago and cost $4000, but was incredibly comfortable... But it was ruined while moving, so I had to get a new one. I'm really ambivalent about this one because it's a 'massed-produced' hotel-grade Serta, and the delivery men exchanged it for a new, 10-day-old TempurPedic that just about killed my back. I have NO IDEA of how long this thing will retain its support, but I'll probably have to get another one in about 10 years.
I have a CoolMax mattress, it still feels like the first day I brought it home. :-) Super comfy
omgosh i need a new one lol its sooo...used :p
Never. Mines used. I prefer sleeping on the couch to sleeping on that...thing D:
18 months to 2 years
Never. I've been sleeping on the same mattress for more than 20 years now. I suspect I'll be sleeping on it twenty years from now. Same for my three pillows.