My nephew (soon 7 years old) has become just one Christmas wish: Lego, Lego, Lego - namely from the Star Wars - series. He immediately assembled after the mess in no time and extensively played the rest of the evening so. Meanwhile, Christmas is quite a while ago, but the Star Wars - Legos are still his favorite toy.
For durability you need at Lego - I think - say not much - Lego is and remains simple Lego!