It probably depends on whether you want to be a psychologist or an accountant? Since both lead to professional qualifications it might be wise to choose one or the other? If psych is just something you want to dabble in, just for curiosity, then it might be a good option.
However, if you want to be a registered psychologist, you might want to focus on psych because you need at least an honours year, which can be quite competitive for entry.
Same goes for accounting. Not too sure about accounting, but I know that I’m actuarial studies, elective space is used to satisfy further accreditation (AIAA). With double degrees, most, if not all of your electives are used up by the additional degree, so you might not be able to use them for CA/CPA units (if that’s what you’re gunning for).