How do you know when to switch to freezing milk?

Ka

I’ve been exclusively pumping since my LO was about 1 week old. He’s 9 weeks now and I feel like over the last week or so, my supply has really regulated.

I used to just keep all the milk I pumped in the fridge and I was usually only about 2 feeding ahead. But now this is the supply I’m constantly running... how do I know when to start freezing milk?