Allow All Users To Add List Items But Only Certain users To Edit Them (SharePoint 2013)

Question

How do we allow all users to add items to a list, but only allow certain users to edit the list items? Site is SharePoint 2013. We have tried creating custom permissions. That does not seem to work.

Answer 1

I've setup a custom list on my SharePoint Foundation using a custom permission level to accomplish this.  I setup a custom permission level on the site called 'Add Only to Lists'  which allows adding an item to the list and setup the group with
the default read and the custom permission level and it works.  The users in the group get the add item but do not get edit item, not even items they created themselves.
Any users who should have full edit permissions can be setup under the normal edit/contribute/design permission level and work normal.
Below is the Role Definition pulled via PowerShell and Role Assignments on the list in question.  As well as a picture showing what it looks like to something assigned that role level.
Role Definition
Name : Add Only to list
Description : Can add items to a list but cannot edit or delete
Type : None
Hidden : False
Order : 2147483647
BasePermissions : ViewListItems, AddListItems, Open, ViewPages
List Role Assignments
Member : Home Visitors
RoleDefinitionBindings : {Read, Add Only to list}
Parent : IT Equipment Request
ParentSecurableObject : IT Equipment Request
The user can create a new item, but cannot edit items - not even items he created.