It's taken me a while to realise that things going wrong for your story's MC is the simplest way to progress the plot. An event going wrong triggers their next move, even if you didn't have their next move already planned. But do all these events have to go wrong, or is it just as important for some things to go 'as planned' ?
I'm a big believer in 'rest periods' during stories. So I think that yes, it's okay for some events to go as planned. But I also think something needs to arise from these events that wasn't evident beforehand. It can even be a happy coincidence, a new relationship, a eureka moment. But it should move the story forward. Something should probably change as a result of the event. I think writers should get into the habit, while writing their first draft, of asking themselves this question: What is this scene supposed to accomplish? If you do that, you'll be on track to keep the story moving forward. It shouldn't require every scene to pose some kind of a problem. However, it should require every scene to accomplish something.
Well that's good because it certainly does that. My only point was that it accomplishes something for the good of the MC. It's helped him in his quest. Obviously too many of these would potentially kill a reader's interest, but so long as you can throw the odd one in.
I don't think there's really a number on these kinds of scenes. The trick is to keep the story moving. For example, some people love to write swordfights, but there's a danger they'll get so wrapped up in the cut and thrust that they forget the reader needs to go away from that scene with some new bit of information or insight. If the hero just keeps winning swordfights—slash slash parry slash, slash slash stab—that's going to get dull, even though the writer might be quite excited about the actual fight. But how many of these do you really need? Good swordfightery stuff has something new at stake each time, and maybe even an increased threat. Or an increased sense of complacency brewing. Or a growing weakness. Something. What is this scene supposed to accomplish? Asking yourself that question really is effective, if you're not sure whether to include a scene or not.
Things going wrong for the MC is certainly the most powerful way of progressing the plot, since it sets the MC challenges and gives them further motivation to proceed. But its certainly not the only way. In my WIP, the MC has a clearly outlined plan at the start of the novel, and the antagonist also has a plan. Both of which, of course, are mutually exclusive. When they finally clash, both sides are forced to reassess their position and improvise accordingly. The benefit of this also is that the directions that the events take are less predictable but still remain somewhat natural, that the MC is adapting to events as they happen, rather than following a predetermined course (this is easier if you are pantsing, rather than plotting out the entire novel).
