In a large project, you would divide the main goal into smaller, more mangeable goals. As you work toward the main goal, you could judge your potential for success by looking at your ability to meet the smaller goals. These smaller goals would be called “interim milestones”. Milestones comes from actual stones that would be placed along a road to mark the distance.

you will need interim milestones, especially for a long-term project I added "need ". . Read it again. The meaning is obvious. . "interim milestones" are one way to know if your project is going to be successful by having a way of measuring success. . That is, they are milestones, subordinate goals, partial goals, acheievements, that are expected before the end of the project, so you can tell how you are going. Example: Project aim. Get to mars. Interim milestone: raise money Interim milestone: build a rocket Interim milestone: raise more money Interim milestone: get to the moon Interim milestone: raise even more money Interim milestone: get to mars Final goal: achieved. Interim milestones usually have a time schedule attached, that is predicted dates.