What is a recommended time interval between flush if brake fluid in Honda Accord Sedan

Every 30,000 miles or 24 months, whichever comes first. This link may help:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-5.html#post619000

Thank you. It's very useful info link.
Honda's manual recommends change interval 3 yrs.

I do my Toyota every 3 yrs. My last Toyota had 232K miles without a front caliper replacement in 18 years. The rear wheel cylinders were replaced once.

It does make a difference. I also replace the bleeder screws at the same time. They corrode.