Nope, and I went to skool for meny yearz.
Like bordelond, I’d heard of him. And even heard of his letters to his son, but that’s as far as it goes.
A satirical writer whose name I’ve long since forgotten had a chapter in a book of his titled, “Lord Chesterfield’s Last Letter To His Son”. The ‘letter’ read, approximately:
Dear Junior:
Get lost.
Dad
ETA: of course, I use Teh Google after posting. The writer was Jack Douglas, who I’ve not otherwise heard of, and the book was My Brother Was an Only Child.
I know the name and probably at some time I knew who he was. As I age, I retain much less.
Same here.
The name was vaguely familiar but I can’t honestly say I knew who he was. Not familiar with the quotes either.
He actually used both separately, in letters which were then published in his Letters to his Son. But the pence and pounds version, which is surely the more famous, is a quote which he attributes to someone else (William Lowndes).
As for the OP, I’m going to disagree with everyone else and say that I think your friend has almost certainly got it absolutely right.
Chesterfield is not a household name and I’m not at all surprised that no one (apart from Thudlow Boink) is claiming more than the vaguest familarity with him. But that’s not really the point. How far will the reader actually need to know who he is? Or is he just being cited as the coiner of a particularly apposite quote? Because if it’s the latter, there’s no harm at all in not identifying someone whom only some readers will have heard of (and then probably only at the level of he-was-some-eighteenth-century-guy). Those who haven’t heard of him will just read on, perhaps only momentarily pausing to register the thought that this seems to be some guy that they’re being expected to be able to identify. The thing is that the alternative is just as bad. Those who have heard of him (however vaguely) will probably find any explanation both clunky and patronising. How dare the writer assume that I don’t know this! And does this mean that he or she had to look this up to be able to tell me? The issue is therefore not ‘is he is someone the reader will know?’ but ‘is he someone the writer can get away with not identifying?’
As to whether Latin quotes need to translated, that depends entirely on how famous the quote is.
Read only the first spoiler box: There’s a quote about “All cats are grey in the dark” meaning, I believe that fucking ugly chicks is ok when you can’t see them. And I think he’s the originator of the “Publish and be damned” response to a blackmailer.
I don’t mind the odd quote or the unfamiliar word in a book. I’ve used them myself. My issue with Lord Chesterfield is that he’s quoted several times, and his one Latin quote that’s called “famous” , as far as I can tell, isn’t. By that time, it seems to me that common courtesy requires you to tell your audience who the fellow you’re quoting so heavily is. I even think that the author would agree. It’s just that he thought Chesterfield was so well-known that there wasn’t any point in it (even though he did identify other people he quotes, who I would think were even more likely to be known to a general audience).
The writer isn’t by any means obligated to identify his source beyond giving the name, but when he hammers on it and apparently expects the audience to know that person, and see the quotes as well-known old friends, it’s worth pointing out that they are, in fact, total strangers, and they ought to be properly introduced.
This is who I thought he was talking about. And I’ve only heard of Chesterton because you’ve brought him up on the boards so many times. Never heard of Chesterfield. And I have a bachelor’s in English literature, for what that’s worth.
That’s rather prettily put! 
I’ve heard the name, I don’t know who he is.
I was clueless about who he was.
Ahem 
Here’s the link: http://www.answers.com/topic/never-put-off-till-tomorrow-what-you-can-do-today
The name was familiar, but not enough to recall who he was or what he was known for. I didn’t make the connection until I opened the spoiler and saw “administrator of Ireland,” which made me go “Oh, that guy.”
And even then, other than knowing that he was one of those Literati politicians that were prevalent back then, I don’t know a whole heck of a lot about him, and have never read his books.
The name was familiar, and I’d seen him quoted, but I really didn’t know who he was.
The name was familiar, and I remembered that he was involved somehow with Johnson’s dictionary. I don’t remember exactly how, though.
There is also a beer from Yuengling named for him too.
I think it would have been better if you’d given one or two of the quotations in the unspoilered part of the OP. However, I still wouldn’t have matched them with the author - much less if they’d been in Latin. All I can say of the name without doing a search is that it seems familiar.
I read some of the better quotes from his letters to his son, and thought he was pretty clever. Then I read Dr. Johnson’s take on him and realized he was clever, like a weasely courtier should be.
Still, if he lived up to his quote; “Wear your learning like your watch, in a private pocket; and do not pull it out and strike it merely to show that you have one,” he was a better person than many of us here.
Lord Chesterfield is famous in the exact same sense that George Santayana and Lord Acton are famous.
Practically EVERY educated person can tell you that that Santayana wrote “Those who do not remember history are condemned to repeat it,” or something like that, but almost nobody can tell you much more about him than that.
If I mentioned Lord Acton to a reasonably well educated person, I’d expect that person to say, “Absolute power corrupts absolutely.” But I wouldn’t expect him to know anything else about Lord Acton.
If I mentioned Lord Chesterfield to the decently educated people I know, most would probably vaguely remember some variation on his famous remarks about sex. Most won’t get it exactly right, but most would probably remember that he told his son something like “The pleasure is brief, the cost outrageous, and the position ridiculous.”
I wouldn’t expect most people to know much more about Lord Chesterfield than that (I certainly don’t!).
The name sounds vaguely familiar, from a card game my sister had when we were growing up. It was called “authors” and was like hm, Fish or Rummy, where you had to get the same cards into a book. I hardly remember it, but that’s what seems most familiar to me.
I would not know Chesterfield enough to know he’s “famous” for anything.