My question is, do most people really need unlimited data on a phone and can I safely downgrade to a current plan so I can tether?
The irony of your situation is that you're probably not using a whole lot of data on your phone, but if you tether regularly then your data usage will go up.
I have five members on my family plan. Of the five, three rarely go above 200 MB of usage per month (and some don't even break 100 MB - they're frequently in wifi-covered areas), one rarely goes above 400 MB in a month (tethers the computer for email and web browsing), and one touches around 1 GB per month (uses Pandora to stream audio during long daily commutes during the work week). We have a 10 GB shared plan, but even with the five of us we rarely break 2 GB. Obviously a sample size of five people doesn't dictate your own usage, but I view us as something of the average. We're not particularly trying to ration our data by barely using our phones unless we're on a wifi network, either; this is just normal usage for us (email, web browsing, sending images through iMessage).
If you're used to doing very bandwidth-intensive things, such as using Youtube all the time, then your usage will likely be much higher.
Assuming your usage is similar to ours, then the "unlimited" plan is a waste. Combine that with the fact that AT&T doesn't have any true unlimited plans (they seem to throttle your speeds once you hit a certain amount, something that
PaulNY seemingly encountered), and it seems really pointless. On the other hand, tethering is incredibly useful.
