I can't give you much perspective, because my son is only 3.5 right now. I did, however, want to commiserate and share a couple of techniques that seem to be working for us. After years of happy compliance, he's started not listening when I ask him to do things, leading to my frustration. Yelling got me no where - I think it undermined my authority when I had to resort to it. I recently switched my approach - if he doesn't listen the first time, I go over, move him away from what he is doing (even just a step), kneel down, look him in the eye, and explain to him that he needs to do what I asked. Sometimes, I have to add that he will get a consequence if he doesn't do what's been asked, but often I find that simply getting his full attention when making the request works (at least for the past few weeks - we'll see how long it keeps up). If I threaten a consequence, I have to follow through (which sucks), but it leads to results. Time-outs don't really work for my son - the consequence has to be meaningful to him in order to be effective (loss of a favorite toy for the afternoon, for example). As for putting things in his mouth/nose, how about removing all toys listed as unsafe for kids under 3, and explain that he'll get them back when he's learned to stop putting them in his mouth/nose? If he's stuck with only baby toys, maybe he'll be incentivised to change his behavior.