请教: 后院邻居要换 fence

today,  my neighbor stopped by my house and told me that they would replace with the new backyard fence , it takes two days next week.   They are the family who shares the backyard fence with us.    We don't know them and met him the first time today .  He came to my house and wanted to give me a heads-up about the fence work,    so I can be prepared .     He didn't mention anything about the cost, nor discuss with us if we should share the cost.

Looking for advice if anything I need pay attention about  my neighbor's fence work.    Thanks.