It's easy for toddlers (and adults, really) to get attached to specific objects or pieces of clothing. Because your baby is growing so quickly, she is especially at risk of growing out of clothes before she is quite ready to part with them. This can lead to tantrums, desperate pleas to wear a certain shirt or sweater, or a refusal to wear any shoes that aren't her light-up sneakers.
You'll want to help, of course, but it's not always easy. You can't force too-small shorts to fit again, and you can't have your baby walking around the grocery store with holes in her shirt. You may find yourself in a situation where you need to, somehow, convince your baby that it's time to stop wearing her favorite thing. Convincing your baby and helping her cope with the loss of a favorite item can take a few different forms.
Sometimes a clean break is the best option. One day her favorite dinosaur shirt is here, the next day it's gone. Who knows where it went! But hey, look at this giraffe shirt - pretty cool, huh? Soon enough, you'll have a new favorite for your baby. And if not...maybe keep the dinosaur shirt in your closet for a little while, just in case.
If you know a rip-the-bandage-off strategy won't go well with your baby, you can try a gentler method. Replace the beloved object with something similar without taking the original item away. If she goes for the tried-and-true favorite, suggest the new item "this time." As your baby (hopefully) grows to like the new item, you can phase out the original.
Hey, it's not the worst thing in the world if your baby keeps an extra article of clothing in her dresser. Tell your baby that even though she can't wear it anymore, she can totally keep it around. Sooner or later, she will forget all about it, and you can quietly send it to the clothing afterlife.
If you don't want to keep a clothing item but don't want to get rid of it, just change what it is! An old shirt can become part of a blanket, a cover for a pillow, or just a shirt for a stuffed animal. Shoes, pants, and dresses are a little trickier, but there are tons of suggestions for repurposing children's clothing items online. If you have too many outgrown clothes to upcycle, try asking your baby what she would think about giving her beloved item to another child who needs it. Maybe it can become someone else's favorite piece of clothing!