Will last for about 3 years I reckon; we've had ours for 2 and its showing signs of wear (for example the articulated joints, tops and bottoms of keys) and corrosion. For reference, the instrument is cleaned often and reasonably regularly maintained (oiled)
Its just about ok for a 6-7 year old to start learning. Don't expect much more and dont expect any re-sale value. In fact, its likely that after 3-4 years of use it wont be good enough for a hand-me-down
On the plus side, the sound is actually ok and it is definitely useful for a young child to learn on. Perhaps even for a saxophone-curious adult who does not want to spend too much.