Sleep is so important for a happy baby. Baby's Day allows you to record how often and how long your baby sleeps. The additional columns mean you can easily see how other daily events link in with sleep patterns.
So, having separate columns for 'In Bed' and 'Sleeping' means that you can see how long it takes your little one to get to sleep once they are in bed. I have sheets that show my son 'Crying' and 'In Bed' for twenty minutes, before moving to 'In Bed' and 'Sleeping' for half an hour. A month or so later, when he (and I!) had mastered daytime naps in his own bed, it shows 'Awake' and 'In Bed' for five minutes and then 'In Bed' and 'Asleep' for a couple of hours.
Being about to see this really gives a sense of achievement and motivation when the going gets tough.
I included the 'Bath' column because so many routines include a bath before bedtime, and it really does seem to work.
If your little one falls asleep in the car or buggy when you are 'Out and About' you can still record this so you know what baby needs when you get home.