You're right Saffi - they do change. Just when I thought I had Katrina all sussed out she changed from a feed - play - sleep pattern to a feed - play - feed - sleep pattern. Then when I'd got that down pat, she changed back again. So it's really important to get to know their signs because then you can adapt accordingly. If you're just going by the clock or what they did last week rather than how they seem right now, it's harder to figure out what's going on and everyone ends up frustrated (and tired).