I get sinusitis at least 4 or 5 times a year?

Too many: That is too many infections per year. The average number of colds in adults is 3-4 yearly. Estimates are that 5-20/1000 colds become sinus infections. Make sure that you are waiting 7-14 days treating the symptoms before going on antibiotics. Bacterial sinus infections show with worsening symptoms over 7-14 days or persisting fluctuating symptoms lasting more than 3-4 wks.