Add note to README on precision of scheduled job timing

Author: j4mie

README.md

@@ -136,7 +136,9 @@ If you'd like to create a job but have it run at some time in the future, you ca
 Job.objects.create(name='scheduled_job', run_after=timezone.now() + timedelta(minutes=10))
 ```
 
-Of course, the job will only be run if your `python manage.py worker` process is running at the time when the job is scheduled to run. Otherwise, it will run the next time you start your worker process after that time has passed.
+Of course, the scheduled job will only be run if your `python manage.py worker` process is running at the time when the job is scheduled to run. Otherwise, it will run the next time you start your worker process after that time has passed.
+
+It's also worth noting that, by default, scheduled jobs run as part of the same queue as all other jobs, and so if a job is already being processed at the time when your scheduled job is due to run, it won't run until that job has finished. If increased precision is important, you might consider using the `queue_name` feature to run a separate worker dedicated to only running scheduled jobs.
 
 ## Terminology