cherishing the "lasts"

I don't recall where I read this, but I do remember reading it.  Someone had suggested that while you watch your child(ren) grow up, don't just concentrate on their "firsts" but also their "lasts".  It's so exciting to see your baby grow into a toddler (and onward, I imagine) that you can lose those last precious moments without even realizing it.  I've tried to make a conscious effort to record as much as I can in a notebook to later document in a book I have for Delia.  You think you will remember the exact date and time that your child either did something for the first OR last time, but I'm sure it will elude you the more memories you have to hold.  The "firsts" are easy to notice....first smile, first time clapping, first tooth, etc.  The "lasts" become a little more difficult to pinpoint.  Did I realize the last time she would wake up in the middle of the night to nurse?  Did I enjoy every second of the last time she nursed ever?  Did I know this would be the last time she fit into that adorably cute outfit I love so much?  I try to pay attention to these kinds of things in the time frame that they might occur, but it's hard to know.  I do know one thing for sure right now.  Yesterday was the last time she had a bottle.  I was coming to the end of the can of formula and being just a few days shy of her first birthday, I didn't want to buy more.  So, I picked up some whole milk at my trip to the grocery store on Monday evening and this morning she had her first sippy cup of milk, bringing an end to the season of bottles.  I'll admit, there are a lot of pros to giving up the bottle.  I hate washing those things, buying formula and having to make sure I always have enough with us should we leave the house.  At the same time, it's just one more step from babyhood to toddler-hood and each of those steps seem to be very bittersweet.