they may shed every other week when young as they mature they may shed the same or every 3-4 weeks, but don't be discouraged if you don't notice because it maybe during your sleepy hours and they may eat it all.
When my leo was tiny, and growing like crazy, she was shedding every 7-10 days. Around three months old, she began stretching it to two weeks. Now, it depends on her appetite. When she's eating more, she'll shed every two weeks; and when she's going on a diet, she'll shed every three-four weeks. I don't think she's gone longer than that yet. Remember it can be different for each leo!