I've had mine for just over a month. Started holding it 30 minutes a day (took 15 mins just waiting for him to open up) but then bumped that up to an hour a day. Once I started holding it an hour a day I noticed a HUGE difference in his temperment very quickly. He's more calm now and has learned to trust me, he's not so jumpy with movement around him, he tolerates me walking around with him, and now it doesn't take him 15 minutes to open up, he opens right away and starts exploring.
Should mention that I don't handle him for 2-3 days after feeding, but other than that, I hold him every day.