I've noticed that many of my friends and neighbors don't understand how the lifeline works, when it comes to requesting an ingredient.
I usually have to go to their farm and explain step by step, to find the facility that needs the ingredient, open it in the Facility Manager, and then click on the + sign to send a request for it.
If I'm out of leather (which seems to be wwwaaayyyy too often), I find one of the facilities, such as the shoe factory, and then click the plus sign on the work boots and send a request to my friends and neighbors for it. They see the request on their pages and click on it. They get 1/2 of what I've requested!
Hope this explanation helps people.
Plynn
