I haven't moisturised my Mulberry ever since I got it almost 2 months ago. All I do is spray it liberately with Collonil Waterstop and that's it.
If it's brand new and you worry that the leather is a bit dull, don't worry, just wear it a lot until it softens up then now and then buff it with the dust bag, to blend the minor scratches etc. That's what I do with mine anyway and the leather has developed a slight sheen which I love. But mine is light NVT by the way.