I think the issue will be **milk **with the tea. Most hotels that have coffee stations in the room, stock them with individual creamers (half & half which is half milk and half cream) or pkts of coffeemate artificial powdered crap.
Drugstores like CVS, RiteAid, Duane Reade etc and convenience stores like 7-11 will have half-pints of milk.
Just bring some with you. I’m American and I usually pack some tea bags for travel within the US. Why would I want to waste time during my trip looking for a supermarket?? And if I did find a supermarket and buy a box of tea bags, then I’d still end up with a box of it to carry around for the rest of the trip. Much better to pack exactly the number I need for the trip in a ziploc bag.
This is probably the case as well unless tea culture has changed in the 15 or so years since I’ve stopped having dairy in my tea. Back then it was a crapshoot as to whether you could find any dairy at all let alone milk, and many waitrons wouldn’t even know if they had any cream-based dairy or not (isn’t that, like, their job?) (I tried various ways of asking, but the phrase “do you have any half and half or cream or milk” worked but was too cumbersome, and “do you have any dairy creamer” was met with blank stares, and “do you have any creamer” most often produced artificial creamer.)
Bring your own Tea, absolutely.
It is not that we do not have tea here, it is not even that we do not have good tea here.
But we absolutely do not have good tea EVERY PLACE here.
Better to have it with you than to search around for a shop selling good tea.
And restaurants generally tend to serve mass packaged tea of ill repute
Surely you jest?
Coffee with sweat cream, caramel, chocolate, coco, mocha, raspberry sauce, etc.
We have coffees that rival any dessert for sweetness, served over ice no less.
Some of it i look at and wonder, is there any room left for the coffee? 
Eeeeewwww.
As I understand it, in either country, you can get really great coffee or really great tea by going to a place that specializes in it. The difference isn’t in the really great products; it’s in the merely decent ones. Here in the US, you can get a decent cup of coffee (at least so I’m told; I don’t drink it myself) in most diners and donut shops, or in the ubiquitous coffee shops, but such places, while they’ll usually have some sort of tea available, it’ll usually be terrible. In the British Isles, meanwhile, decent coffee is harder to find, but you can get decent tea all over the place.
As others have said, your hotel is likely to have only bad tea. It’s not a guarantee: If the hotel is run by a tea-drinker, they might spring for the extra few cents a cup to get something good, and a high-end hotel might get high-quality everything just as a matter of principle. But, yeah, it takes so little effort to bring your own that there’s very little reason not to.
And as an aside, I’m always amused by Orwell’s essay on tea snobbery, where he goes on a tirade against people who add sugar, because it drowns out the taste of the tea, and people who add sugar don’t like tea, they just like sugar-water… but then goes into the proper way to add the milk, which drowns out the tea flavor to a far greater degree than a small amount of sugar.
Harvested from recently-besunscreened Florida runners.
The movie The Second Best Exotic Marigold Hotel had an interesting perspective on tea in America. See the clip here (the tea commentary starts about a minute into the clip).
This is 100 percent false. Coffee in the U.S. is generally as bad as the tea in common coffee shops, diners and restaurants, but that’s a story for a different thread.
This point has been made by other posters but I think it’s worth reiterating succinctly:
Yes, bring your own tea bags, but when you get here what you will find is that the quality of American tea bags is the least of your problems.
Restaurants and diners and other common places have no fucking idea how to make tea. They’ll hand you a cup of warm-ish water and a tea bag that you’ll have to dunk yourself. They even seem to think that you can use that same twangs for a second cup.
If you’re really unlucky, you’ll wind up at a place that offers you a selection of tea bags, none of which contain any actual tea.
Getting proper milk or dairy will be difficult. Your hotel will give you powdered non-dairy creamer. Restaurants will usually give you artificial creamer or half and half, which just doesn’t taste right in tea.
I encounter a lot of coffee snobs where I hang out and I’ve never run into this. The coffee snobs I have seen insist that coffee must be taken black.
Maybe it’s just a New York thing then. If you ask for a “regular coffee” here, it’ll come with milk and sugar. If you want black coffee, you ask for “black coffee.”
And I never knew that milk in tea was a British thing. That’s how my mother always has it, that’s how I always have it. Never thought about it at all.
I’ve only known it as a New York local dialect thing, not a coffee snob thing. I’d be shocked that any self-proclaimed “coffee snob” would say to take coffee with cream and two sugars as a matter of course. “Regular coffee” means nothing in my dialect, and if you said it to me, I’d give you a black coffee or perhaps ask (“regular” to me suggests caf vs decaf.). But, then again, I’ve been somewhere where black coffee meant no milk, but it did have sugar. Can’t remember where. Wikipedia’s definition for black coffee says “Coffee, served as a beverage without cream or milk, and often without sugar as well,” so that suggests I’m not the only one to have encountered that usage.
Something i dont see mentioned about southern sweet tea.
It isn’t necessarily just a gallon of tea with 2 cups of sugar.
Depending on who is making it, it can have a lot of other things in it too.
Vanilla, Lemon, Peach syrup, caramel syrup, lime, brown sugar, Kayro and other possibly strange things.
Crazy stuff
All of it though is usually super super sweet to me.
I don’t mind a bit of honey, or a little sugar in iced tea, but i want to taste the tea not boost my tooth decay 
“Only in Canada? ::sip:: Pity.”
Yeah it must be a New York thing that has nothing to do with coffee snobs. If a coffee snob says “regular,” it’s only a reference to the size of the serving.
In Malaysia, tea is served with sweetened condensed milk added. I thought I could get used to it, but no. And they grow tea there in the Highlands.
While the temperature of the water does matter, I think a lot of tea-drinkers focus too much on it. The quality of the tea itself should come first: A good tea steeped in hot-but-not-hot-enough water will give better results than a poor tea steeped in boiling water (though of course, both are inferior to the good tea in boiling water). Maybe Brits just don’t realize that because the really terrible tea isn’t even available over there, and so the water is the only thing you can screw up.
And I don’t put milk in my tea, but you’d be hard-pressed to find any place in the US where you can’t get milk at all. It might not be sitting on the same convenient little side-table with the sweeteners and “creamer” and stirrers, but if you ask somebody they’ll probably be able to get some for you. I’d certainly expect to see milk available at a hotel breakfast (without even needing to ask for it), because a lot of Americans take either glass of milk or a bowl of cereal with breakfast.
I’m also baffled, in that clip from The Second-Best Exotic Marigold Hotel, what the British lady has against dunking her own teabag in her own cup. It’s, um, not exactly difficult.
It’s not that it’s difficult. It is (1) ineffective because by the time the water is brought to your table, it’s too cold to make tea properly, and (2) ordering a food item and being brought the ingredients to make it yourself.
The link I posted clearly said it’s a New York thing.