I'm one of those thrifty bastards...almost.
I have a Sanyo Katana LX, purchased in January 2009. It still makes phone calls, it still sends and receives texts, and its battery lasts a week with the light use I give it.
I was in the same boat. Up until last month I was using a Nokia 6030 (so, 2005 vintage) as my cell phone. I didn't own a single handset for 10 years continuously, because there was a couple times I had to replace it for something actually not working on the one I had -- but I'd just go on eBay and buy another of the exact model. I'd disable the internal memory so all my contacts would save to the SIM by default, and I could just move it to a new one, taking everything with me if I needed to. Battery lasted a week with my usage and audio/reception were better than even the more expensive smartphone I replaced it with.