There's a very old quote by one of my teachers: "Don't let mycroft near the novices." And it's true. Because my answer to most questions about bidding is "it depends"(*).
It depends on the system you are playing.
It depends on what conventions you have available, and what conventions you don't use, and what room you have to replace a natural sequence with a convention.
It depends on your style for opening (especially pre-emptive openings).
It depends on your opponents, and their system and agreements - and skill level and state of the match and whether you have a history (or, indeed, a history).
But a lot of that applies to your constructive [when the opponents aren't (yet) in the auction] bidding only. Even the "what do I do with this hand after partner's 2♥?" question - which frequently isn't a "our hand" auction - depends strongly on what you expect for partner's 2♥ opener.
When the opponents are in the auction (and not just preempting) - when it is competitive, in other words - a lot of "that depends" goes away, because the goal stops becoming "find our best contract, giving away to the defence only what information is necessary" and becomes "win the partscore" - go -100 into -110, or +110 into +100, and definitely avoid -800 (**). And those rules are much more easily prescribed by results - there really is "one right way" to do it (or at least it's much closer). Hence all of Tom Au's takeout double questions and "why is this 9-count worth more than this 13-count (or less than this 5-count)" - there's one right way to do it, because wrong ways can get punished more often; and good players know when to punish.
Defence is even more than bidding defined by the math. Sure, signalling choices change the information available, as does the auction, but the "right choice" based on the information given is all down to statistics (or "only hope"s), and players good enough to play at world championship level know how to work out those statistics and only working positions. So when someone plays "a non-standard style", and it works measurably better than the way everyone else knows is right, then either the math works out and "everyone" starts playing that way, or it doesn't work out, and people start looking for other reasons it works for "someone" and not, say, for them.
What Joe says is also correct, however, especially in North America. There's A Style (which because I'm an old C hand, I call the "One True Bidding System". People either get it or they don't) that is so common and so universal that I can sit down with anyone, agree "2/1, with [defence to NT], [preempt style], and [keycard version]" and a) partner can play it, and b) we'll get 80+% of auctions right. And so, unless otherwise specified, questions asked are assumed to be in that framework. And in that framework, at least for the first round or two, there is very often "the answer" - imposed by system.
What you say in your comment to Joe's answer is also true - 12-21 (Opener's 1-of-a-suit) is a massive range (***), and there are some serious holes in a standard/ 2/1 system that need to be covered by conventions, mostly around resolving that massive range. And others that players like to cover with conventions, even if it's not necessary. And there are choices in what, if any, conventions to play and what holes to live with. And there - is where, even in an assumed 2/1 base, "it depends".
So, yes, "it depends". But frequently - especially in newspaper bridge columns and periodicals (The Bridge World excepted - it deliberately aims at experts) - unless they're trying to stump for their pet methods, there will be "the answer". In fact, the hands are chosen partly so there is "the answer", most of the time - with maybe one outlier that shows potential problems or potential choices.
And you can see from the number of side paths and "mostly"s and ... even in this answer, that "it depends". And that maybe I'm not the best person to answer this question to a new/non-bridge player...
*) new players can't use "it depends", they need "the answer". Even if it comes along with "as you get more experienced, you will find that there is another answer that works better - or works better for you. But for now, this." And I'm horrible at doing that (and frequently can't think down far enough to see it), so all I do is confuse.
Note that when they get slightly more experienced than "novice", where they can see the interactions, I am considered a very strong teacher, and many come to me with these kinds of issues. But, still, "it depends"; and what's right for me, or what's right for my partnerships, can very much not be right for the questioner.
**) Okay, at IMPs and money bridge. Matchpoints has its own reward structure based more on frequency than size of wins and losses, and that limits the amount of the potential win or loss in a way that "real bridge" doesn't. But most bridge writers are most often either discussing high-level events (which are more often long IMP-scored team matches) or advice for "kitchen" level players (who score rubber or Chicago - "money bridge", even if there isn't any stakes).
***) In fact, a majority of systems that aren't OTBS (or simple swaps to weak NT or the like) have an explicit goal of limiting the one-of-a-suit openers. Whether it's Precision (10-15) or Polish Club (12-18ish) or even Strong Pass (8-12). Even K/S (the weak NT system I play) has a goal of making at least the 1♣ and 1⋄ openers better defined, by taking out most minimum hands (either to 1NT or pass). Of course, they all do it by making something else harder to deal with. If that weren't the case, there would truly be OTBS.
