Question for Moms who already have kids

Britt • 👦🏼💙 May 27, 2016 ;👼🏼 12weeks Nov 2017 ; 🌈 💙🧒🏼March 8, 2020 💖👶🏻 Aug 3, 2021

Do you get a new crib mattress for each baby? Or do you reuse your mattress? My 3year old is in a full size bed now- so we still have our crib mattress in our crib. Not sure if we need a new one or not