A contractor that I've hired in the past had some instant lawn (i.e. rolled up lawn) left over from another job, and offered to lay it for me on my path (for free). I said that the path wasn't ready, but he insisted that he had an expert layer to do the job. I was away that day, and the new lawn looked nice. After a few weeks the grass started to die. I watered it every day but there were large patches that wouldn't grow. P.S. it's summer here!
Next door, more instant lawn was delivered on a pallet using a huge truck. Apparently that was the wrong stuff so the truck came back with more lawn and took away the old lot. That took an hour or so. I said to those contractors that if they had any lawn left over I would get rid of it for them. Sure enough there were quite a few square metres of lawn left over, because most people can't work out areas properly, even for a simple retangular shape.
I was going to insert the new lawn in place of the dead patches in my path. I dug up the dead bits, to find that my contractor had left the path as it was, with a plastic membrane on it and covered with scoria. So, no soil. Also under the lawn were two squashed 2-litre mik bottles and about 10 bricks and assorted bits of concrete.
I have spent a day digging up all the old grass, removing the plastic and scoria and rubbish, putting in fresh soil and laying the new instant lawn. It looks really good! I know nothing about laying lawns but I can do a better job than a professional (well those ones anyway).