How many months can you wait to bleach ur hair?

So i bleached my hair for the first time in September. I went blonde.. i am a brunette. On nov 5 i have an appointment to bleach it again on the top and retouch... so you gotta go every 2 months? Cuz i dont want my hair falling out... it already almost fell off when i bleached it well the split ends. 😞..