R. v. Whiston, 2024 ONCA 79, February 2, 2024, at paragraphs 3 to 5:

We accept the appellant’s point that there should not be multiple motions regarding the same evidence. This is a basic proposition that applies both to the prosecution and to the defence, but perhaps especially to the prosecution.

That said, there is no absolute prohibition against multiple attempts to introduce the same evidence. It is up to the judge hearing subsequent motions, relating to the same evidence, to decide whether they should be entertained. In this case, the first three attempts were rejected by the court as a result of procedural deficiencies. In addition, the first two did not rule on the merits of the admissibility request. Further, the first two attempts were dismissed on the express understanding that the prosecution could renew the application on further and better material.

The decision to allow or reject subsequent motions on the same evidence is a matter for the discretion of the trial judge. It is recognized that prosecutions are fluid and that a ruling made at one point may need to be revisited at another point if circumstances change: R. v. La, [1997] 2 S.C.R. 680 at para. 28. In this case, the trial judge viewed the decision in R. v. Langan, 2020 SCC 33 as changing the evidentiary landscape and warranting a revisiting of the admissibility of the evidence. We do not see any basis to interfere with the trial judge’s exercise of his discretion. The appearance of fairness is engaged as much by allowing the admission of probative evidence as it is by the multiplicity of attempts to do so.