Baby bags can quickly become portable cupboards full of 'just in case' items. A more useful approach is to consider the length of the trip, access to supplies, feeding needs and the season. Pack for the outing you are actually taking, with flexibility for ordinary delays.
Start with the essentials for your family
For many outings, that means nappies, wipes, an appropriate change mat, spare clothes, a bag for soiled items and whatever feeding supplies your child needs. Add any medically necessary items as directed by your healthcare team.
Check that creams, medicines, small objects and cleaning products are safely contained and inaccessible to children. Keep relevant emergency details available as appropriate.
Match the bag to the trip
A short visit to the shops may need less than a full day away. The goal isn't to carry the fewest objects; it is to avoid items that make the bag hard to search and heavy to carry.
If you use a pram, do not hang a heavy bag from its handle: the ACCC warns this can increase tipping risk. Use the pram storage only as directed and check loading limits.
Build an easy-to-find layout
Keep a small pouch with changing essentials, one compartment for clean clothes and another for feeding supplies. A separate waterproof bag can help contain soiled items. Use whatever pouches you already have before buying new organisers.
Avoid opaque bags full of loose small items. You should be able to locate a nappy or spare outfit quickly without emptying everything onto a public change table.
Review after each outing
Restock what you used and remove the things you carried but never needed. Over time you will learn whether extra clothing, a hat or a different size of wipes packet makes sense.
For outdoor trips, consider local weather and sun protection, following advice appropriate for your child's age. A little preparation is useful, but no bag can anticipate everything.
Choose the bag last
If you are shopping for a new one, test access with one hand, strap comfort, how it sits in your normal mode of transport and whether it can be cleaned. A normal backpack might suit you just as well as a specialist nappy bag.
The right bag is the one that makes leaving home easier—not another object that needs a complicated packing system.