Using "one" when you want to address a person in general, not specifically the reader. This was considered good practice in general. Consider this:
When the stakes are high one is often tempted to cheat.
Verses:
When the stakes are high you are often tempted to cheat.
You might prefer the former to the latter because the latter comes across as very accusatory. This is really the only circumstance I will use "one" as opposed to "you." Generally, except in very formal writing, "one" comes across as rather pretentious or old fashioned. It puts distance between the reader and writer which might be a good thing, but often isn't.
As another commentator mentioned, often it is possible to rewrite in such a way as to avoid both. For example:
When the stakes are high, cheating is more likely.
I guess I kinda can add something of value here. I'm AmE, and I do sometimes use those colloquial, non-standard spellings, such as "kinda", "sorta", and others -- intentionally. (There are other non-standard spelt words which sometimes are used for similar intentions: gonna, gotta, hafta, oughta, supposta, usta, wanna. Those examples happen to have the infinitival marker "to" incorporated into the word.) These kind of words usually have the exact same meaning as the more standard spelled expression (but not always).
Anyway, the reasons why I, personally, might use them are:
explicit hedging because I know that I'm over-generalizing or slightly misusing a technical term. (And so, for informal discussion, I sometimes use these words instead of more formal hedging expressions around those "misused" technical terms to indicate that I'm using the technical terms loosely.)
implicit hedging because, although I think I am saying it right, I am too lazy to verify by looking it up, and so, to play it safe, I put in an informal hedge word, just in case.
to give the post an informal feel, especially if I've been droning on like it's been a lecture.
to indicate that I'm an AmE speaker, and so, the reader should take that into mind when reading my posts.
So, those are my excuses.
(ASIDE: Recently on another forum, I've used colloquial spellings and non-standard dialects when engaging in a grammar discussion with an arrogant, know-it-all pedant troll who was completely wrong. Oh, I also did a whole bunch of copula droppings (e.g. "You so stupid")--the pedant troll was so naive that he didn't recognize it for what it was.)
Best Answer
I believe most style books advise against using and/or in formal writing. By "formal" I mean in newspapers or novels. If space is extremely limited, most writers would have no qualms about it, as in dictionary entries or footnotes.
The reason is that or can mean either "either A and not B, or B and not A" or "A or B or both" in ordinary language: 99 % of the time, readers will be able to figure out whether it is used inclusively or exclusively based on context. If ambiguity could arise, the writer should add some context to make it clear:
May the test be taken twice? There are several ways to clarify this, though not every way may work in any situation. Suppose the answer was yes:
Suppose the test might be taken only once: