Depreciation – Freehold & Leasehold (non exam related)

I am a part time student, and i face some question during my daily working. It is regarding the depreciation for freehold land/building and leasehold land/building.
My colleague said that IAS 16 PPE does mention for that, but i read nothing. So, please guide.

How do we treat the depreciation (rate) for:

i) Freehold Land = no depreciation, as infinite useful life. if not, why?
ii) Freehold Building = Got this kind of building? Since building is getting older and older, then how to counter the depreciation?
iii) Leasehold land = Apportion based on the leasing period given.
iv) Leasehold building = 2% per annum applied. if the leasing period is less than 50 years, then apportion based on the leasing period left?

Please correct me… thanks.