I would probably get them some kind of older, used gadgets at first. They will be bound to break some things at a really young age, so after they see how it feels to lose something they like, they should be better at taking care of them in the future.
Also, I think it would be important to teach how to play with them interactively with others, encouraging them to play with other kids, even when using different tech stuff. That can easily be done by showing them how to take turns with it, maybe letting them help as you are playing a game yourself, and asking if you can help when they are playing a game, and so on.
As I mostly saw with my parents teaching me how to play video games as a toddler, I quickly got better than them at most games. So it would be awesome to see my kids do the same, and surpass me. (I don't think that would be too difficult, though XD)
I think the right age for them to have a phone is when they don't really think of it as a toy. I think they could learn this pretty quickly if they started calling random numbers with it, and other things they aren't suppose to do. They wouldn't get in that much trouble with it, but how else do you teach them not to do that? You could tell them not to call random numbers or do things like that, but chances are kids will want to find out why. :P