Have had my girls for 3 weeks. They now know their names. I greeted them by name each time they would come out of their bed or come towards me for treats. Now we can say "where's Lily?" and she will pop her head out.
You kind of have to just find the small differences in them. I have three albinos so it was tough at first but it helps if they are different sizes or maybe ones tail is a little dirtier or shorter ect. Youll get the hang of it.