New player question

Hi everyone

I tried searching key words but didn't find what i was looking for so here goes.

When it comes to old generator, the rails, rubble etc is there anything i should keep for later in the game? My paranoia is keeping me from demolishing them.

Similarly with desert tiles, are they of any benefit dried up ?

How can you tell if a tile is useful until you unlock the building or improvement for it?

Thanks for any help, spoiler free if possible.