I am rather concerned tonight because I was not expecting to see any more spotting - this is her first season and it started 2 weeks ago tomorrow (monday).  I thought she was in her second stage by now and it would be over by next weekend.  However after not seeing any spotting for several days she has started spotting red again quite heavily.  Should I be concerned or is this normal for a first season?

My bitches have bled for the full 21+ days, whether or not they were mated.

How do I know when she is out of season?  I have been going by what I have read - 9 days pre-oestrus and 9 days oestrus proper - 18 days in all - obviously I am wrong. Thanks for putting my mind at rest.

28 days is what some people experience.
Each bitch is individual and some tend not to read books
and don't follow the rules ;)

The average season in the average bitch lasts 21 days - but all bitches are different, and none of them have read the books! :D

my bitches first season lasted just over 4 weeks, vets said if it continued into a 5th week to take her in but it did just stop