What are the advantages of pre-cast slabs over slabs cast on site?

                The advantages of pre-cast slabs are following 

1. Pre-cast slabs are light in weight compared to the slabs cast on site. Hence the structure gets less loaded with pre-cast slabs.

2. Quality of the pre-cast slabs is well controlled since the job is carried under skilled supervision.

3. Casting and curing time for a slab cast on site is at least one moth. Installing a pre-cast slab takes hardly a day or two. Hence installing pre-cast slab in an occupied tenement / shop / office is a much better solution.

4. The pre-cast slabs can be dismantled and reused somewhere else.

5. No centering structures are needed for pre-cast slabs.