Idk how common it is for siblings to fight over toys or clothes. My sister and I shared clothes with no problem. We communicated between us and she was older, so ....Wrong. Plan B only exists because “speaking to them in love” proves ineffective, especially when ego and emotions get involved. How many children did you raise? I have so many stories to share.
One story is the constant fighting the girls had over borrowing things. It was madness. I didn’t resort to either corporeal punishment or isolation. Instead, I can up with a contract form. The borrower had to fill it out, including what was borrowed and when, where it was stipulated the article of clothing was to be returned in 24 hours, cleaned, folded and put on the lenders bed. IF the lender didn’t secure the contract, the Complaint would NOT be heard in the Court of Mom and Dad. LOL
We had a strong bond. She was there for me when things were really bad in the home. I looked up to her. We planned the night before what we were wearing the next day.
My children didn't fight over toys except for a stint of maybe a month when my oldest girls were 2 and 3 years old. My girls also didn't fight over clothes. They shared a lot and liked sharing and spending time together.