I find if helps if you give them toys that will allow them to express their naughtiness in a more productive manner.. And let them destroy things that you don't mind them destroying! Frasier was a typical Nethie, while Niles is quieter & well behaved, but loves a good run about in the lounge! For Frasier, things like forage boxes, towels (for him to scrunch up and burrow into, just make sure they're not chewing it), willow balls to throw about - I used to play with him.. Roll the ball to him & he'd either pick it up & throw it back, or box it with his paws! Eventually he'd chew it up
, lots of room to run about in! Niles has always enjoyed burrowing, hiding & jumping onto things, rather than destroying things like his brother. So for toys he now has a wooden house, a bed to burrow in, a tunnel to hide in & so on.
Toys that will bug them into thinking are a great way to challenge their minds & keep them busy! Niles isn't very food oriented, whereas Frasier was a little greedy pig!! So I'd use toilet roll tubes to hide treats in, either by folding them up at the ends, or cutting them into pieces to make a ball with treats inside.. That went down really well with Frasier! Also, they used to have a metal ball that you can stuff with hay & greens. Well, they didn't go for that, but loved it when I put some tasty treats in it instead! They spent hours trying to get them out
Hope some of these ideas help x