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I've got a Verizon 15/5 package over fiber optic. Testing to different servers around the world, generally DL is never slower than about 5Mbps, and often runs 16 to 20. UL is the real problem; sometimes get 5 or even 6+Mbps, but usually more like 3 and often around/under 1Mbps. But, that depends on the server I'm connecting to, not my service provider.
Internet is packaged with TV (pretty crippled basic package) and 'unlimited' phone (can call all of North America for free or nearly free; nice when actually using it). That's ~$140 US/ month. I think it would have been ~$80 for internet only.
uTorrent never breaks ~600-630 Kbps upload ... I'd love to tweak that up to 1Mbps or even 2, if anyone knows any tips. Been playing with the settings on that for half a year now; no joy.
Could'a gone with 45/15 internet package, but really have no need & it'd be ~$100 more / month.
I could live with 1TB caps in any 'floating' 30-day period, so long as the service provider also provided accurate and adequate tools to monitor and shape my traffic. As it is, there's no way to check, it's all guesswork and you find out only when the month-end summary arrives two weeks after the month ends.
Under those circumstances, there should be no caps because you have no 'control' or information to make your decisions.
I currently avg. ~750-850 GB total transfer (UL + DL) on uTorrent alone per 31-day period. ~80% is upload cause I just leave seeding and keep running out of drive space for DLs.

I can't imagine the remainder of bandwidth use (websurfing) adds more than another 50-100GB (probably more like ~20 or less).
Oh. Yeah .. so, no I've not had any nasty calls from Verizon. I even discussed torrents & bandwidth use with their tech staff and they claim that there's no problem, unless they get a complaint that I'm doing something illegal from somebody. So far, no complaints ...

What intrigues me is that in three years, these will probably seem like conservative numbers.

I lived in Latvia for a while; for the past four years I had service that looked pretty much like the numbers posted by Pentium100 from Lithuania. That was ~$20 US per month, and that was a bare wire to the door where I had to provide all hardware & configuration. You DO NOT connect without a
robust firewall like that. Generally the top speeds were good for all of Latvia and parts of Estonia & Lithuania, sometimes a hit in Poland, Finland or Sweden would compare.