At one of my very first outings as a new mommy, I learned the hard way to never run out of wipes. I was nursing my beautiful baby girl when I realized that there was a strange sour smell, and that it was coming from the baby girl. I checked out her hair and fingers and found nothing. I checked her shirt, but that was clean. I checked her neck - bingo. She had some nasty stuff in the neck folds. It was distugting. About the time I figured out a game plan, she had finished eating and was concentrating on the next activity: pooping. Great. New plan: change her diaper, then quickly swipe out the neck yuck and throw everything away at once. I got out the gianormous diaper bag, got everything ready to go, and opened up the wipes container to discover I had two left. Two. One for the neck, one for the other stuff. Not enough. Lucky for me, I was at a new moms group at the local hospital, and my friend - who's baby was five months older than mine - had a big supply of wipes and gave me a handful. I cleaned up the darling baby girl, thanked my friend, and went home to cram as many wipes as I could into that travel case. Then I took a quart-sized ziplock and filled it with wipes, and put that and a clean outfit and a clean diaper in a gallon-sized ziplock and put them into the trunk of my car. Now that I think about it, I'm pretty sure that's about the time I started buying the case of wipes at Costco. Never run out of wipes.
Bonus: Wipes for Sensitive Skin
My daughter was prone to diaper rash, and when she had a bad rash, the baby wipes were very irritating to her skin. I finally figured out to do this: I would take the wipes and rinse them out over and over again until any smell was totally gone. Then I would rinse out the tub, and put in a little water and a little baby oil. Then I would put the rinsed wipes back in and let them soak in the baby oil mixture. This makes the wipes very wet - you have to squeeze out the extra water to use them - but it is much gentler on baby's skin. I know of some moms who would make their own wipes, but I tried that one time and it didn't do it for me.