Is it just something that needs to be remembered along with the verb, or is there some reasoning that can be applied.
That's a good question.
In English we say "It behooves a scholar to weigh all the evidence" but "It is fitting FOR a scholar to weigh all the evidence" and "It is incumbent ON a scholar to weigh all the evidence" but "it is required OF a scholar THAT he weigh all the evidence." They all mean MORE OR LESS the same thing, and any difference in meaning is so fine that no two fluent English speakers will agree on precisely how and why they differ. I suppose some reasoning or rule or historical development could be brought in to explain the differences.
But here is the thing, I don't know what the rule is and I don't really care. I have used and understood all these expressions without every thinking about the rules. Almost everyone attains perfect fluency in their native language without every analyzing it except in the broadest strokes, and those who analyze their native tongue more deeply do not become better readers or writers. Analysis, that is, has no connection to fluency in English and I don't see why it would in Greek.
So, yes, there may be reasoning behind why the dative here and why the accusative there. If knowing this reasoning would help me understand Greek better I would want to know it.
ἴθι πολλὰ χαίρων!