Hi Lou, I don't know how you would know until you get to that stage, maybe just test anything you are keeping long term. Your fresh milk in the fridge with the separation sounds normal though. Didn't want to stress you out, just something to keep in mind, mine definitely went yellowy after being frozen for more than a month and had a slightly funny smell even though still frozen.

As long as he is sleeping lol, hope you are enjoying it, it goes too fast. Xx