Templates won't update

Hi everyone
I am a student learning Dreamweaver MX, and am having trouble with my templates. I have been happily updating child pages from the templates, then all of a sudden they don't update. It is really inconsistent from one day to the next and I cannot figure out what I have done or why it works occasionally.

I remember seeing once in a forum months ago, "there are two or three things that make templates stop updating,"... Of course I can't remember what they were and I cannot find the thread now.

Thanks to anyone who can help me!

Keogh2