Roofing advice

[workingeverysingkeday]

I need a new roof.

Had 3 quotes and one is by far the most expensive but he said they'd put lead in the valleys which is why his quote is so much more. I've no idea what this means.
Do I need lead in my valleys?

Lead is traditionally used in the valleys. Have you asked the other companies what they are using?

The other days a dry valley system

Says

I would always have lead - longer lasting but more expensive. But not that much more expensive.

How much is the quote? What are the dimensions of the roof - roughly? Tile, slate or cement? Including scaffolding & new roof liner?

Is the quote fixed for a period of time or is it an estimate?

The roof is old tile.

We have one quote almost 8k with lead the cheapest 6400 without