I usually wait for an upgrade which is 2 years through sprint I have found that they have the best plan for the money and that to me is more important than the phone.

One of my first phones was an old samsung flip phone that I have here. I waited 2 years before upgrading to the LG Rumor which was a great phone for its time, can play music, record audio/video and had a very basic Internet browser. For my newest phone I waited 3 years to find something that I really liked and chose to go with the Epic 4g. It is capable of doing 720P HD video recording and the camera has a flash as well, also a front facing camera in addition, has a full fledged browser, full keyboard, the phone is very fast. I believe at this point the hardware is way ahead of the software for phones, my phone is capable of processing more polygons per second than that of a playstation2. I think right now has been the right time to upgrade.

What are your thoughts on upgrading?

I update mine about every 1 to 1.5 years.

I use mine mostly for work: voice, email, calendar syncing, and document creation and editing when on the road. Also, I use it for tethering to laptop for internet access when traveling and as a web browser both for work and for pleasure. Strictly for pleasure, I use it to stream the broadcasts of MLB games when I am at work or otherwise cannot watch the games, and I use it to read some of my kindle library when waiting. It has a camera/video camera, but I use it very little. I don't play games on it either.

AT&T apparently likes me (or just wants to keep me as a happy customer because I have an expensive plan), so they always have let me upgrade even though I'm usually well before I'm technically eligible.

Edit: I selected "about1 year or less" as that was the best fit

I was with T-mobile for almost 10 years. They were great and treated me very well. My plan allowed me to upgrade every 2 years (and was cheaper than anything they currently offered!). But they often let me upgrade much sooner if I just asked. That is until last fall. They got stupid and tried to take a hard line. I was a month from being able to upgrade. They refused to let me upgrade early AND they offered crappy phones. They wanted me to pay $200 for a phone that was clearly far worse than the one Verizon charged me $100 for. T Mobile was fantastic a few years ago but they have gone way downhill.