Assuming you put in a solid effort, I do not think retaking the GMAT would be helpful. A 730 is right at the average acceptance, so it’s not harming you in any way.
There’s also a very real possibility, you would go through the cost and energy in studying again, only to receive a 730 again (ignoring the fact you could score below 730 which also exists). Additionally, to an admissions counselor i believe a 730 is identical to a 740 when comparing applicants, and they would move on to evaluate the rest of the applicant’s experience.
The bar I would consider at your stage to warrant signing up for the official GMAT is a 30-point increase. If you did not study much for the 730, or you had an out of character score, lower than your practice tests then I could understand a retake. I wouldn’t register for the official exam until you can score two practice exams in the 760+ range, but of course that means buying material and studying full force without knowing you will take the exam. A 760 could put you in a separate candidate tier for admissions officers, compared to other applicants.
Lastly, keep in mind that your GMAT score may not be the reason at all for your waitlist decision.
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