I've read it has to be used 24 hours after it is defrosted....or is it 24 hours after it is taken out of the freezer?

And why can't we use keep it in the fridge for a few days after defrosting? I've already thrown out a few bottles because we didn't use it within 48 hours from taking it out of the freezer and I am wondering if I needed to. Sometimes it's hard to plan when we are going to need it.