Breeding Female German Shepherds

Question
How often do females come into heat and when is the appropriate time to breed?  I have been given several different answers.  One was to keep the male and female together for 10dys.

Thanks,

Answer
Are you aware of the problem of dogs being slaughtered for lack of homes?  Quite often full blooded German shepherds?  Go to www.petfinder and see how many German Shepherds in your area need homes.  Then go to www.akc.org and read about responsible breeding.  Do you even know what OFA certification is?  I am here to help dogs by answering questions.  I am not here to help people add to the misery caused by irresponsible breeding.