When should we get him a phone? (Real talk needed)

My son is 11 and starting middle school in the fall. Like half his class already has phones, and his mom (we're split custody) is pushing to get him one so they can "stay in touch." I get it but... I'm not ready. He loses everything - his retainer, his glasses, his homework - so a $700 phone feels like a disaster waiting to happen.

But also I don't want him to be the weird kid without a phone, and the custody thing does make communication harder. What's the actual average age for this? And if we do it, what kind of phone + parental controls setup are you guys using?