I heard that corona immunity typically lasts up to 2 years, so you’d need a booster at least once every 2 years.
I've only seen studies suggesting "about 1 year" for the 4 CV's that cause common cold, during which time you can actually be reinfected and shed virus, but do no become symptomatic. MERS depends on the severity of infection, from 10 months to 18 months, and SARS about 2 years plus. Those are the only CV's prior to this one to infect humans. Also, with SARS and MERS, all that was verified was "an antibody response" to deactivated virus, not immunity. I think the bottom line is that we can hope, but we just don't know.