I have been on the pill for many years. I've had occasional spotting if I forgot one pill or took it later in the day. The type of pill can determine how likely spotting is and how strict you need to be in taking it at the same time each day. I've not had an unintended pregancy in 25+ years of being on the pill.
If you don't want any more children, however, I would be talking with your doctor about permanent birth control options, for you or your husband. Vasectomies are inexpensive, quick, and barely painful.