I keep my diaper bag well stocked because there have been too many time that I've been out and realized I needed something I left at home. Here is what I now keep in my diaper bag at all times
I typically always have 4 diapers in my diaper bag at all times
Pampers Swaddlers Active Baby Diapers - (select Size And Count)
I will keep a full pack of wipes at all times and if it's running low I add an additional because you can never have enough
Pampers Free & Gentle Baby Wipes - Target
At least 2 burp clothes because SPIT UP! Theses are great because they can also function as bibs
Burt's Bees Baby : Bibs & Burp Cloths - Target
I always keep a thermometer in my bag just in case. It has proven to be very helpful over the years
Frida Baby : Thermometers - Target
Pain relief is another thing you may need in a pinch making it handy to keep in your bag