This came up in a comment by thenewgreen which I'm having trouble finding, and I think it's a very interesting question.
There's seemingly a disproportionate number of people on Hubski working on projects, family matters, starting new parts of their lives, and everything else in between. For a lot of these things it's not as simple as "I'm going to schedule all of this in Microsoft Project and once items x, y, and z have been finished, I'm done". Life is a lot more grey and less binary than that. When it comes to relationships, personal projects, so on and so forth how do you know you're done or approaching the end? Do you find yourself struggling to close out of things?
Even before graduating I saw the end of the line coming with my involvement in Dadstache Records because I had other things in mind. Even now I'm starting to realize that this blog isn't exactly what I want to be doing and will likely be closing it for a while to think about this some more and how I can better service the local music scene in a unique way.
I saw Spiritualized and Curve open for The Jesus and Mary Chain on the Honey's Dead tour in 1992. You never know when you're done. You decide. This is an important distinction because "knowing" is an internal observation of an external phenomenon while "deciding" is an internal action on an external condition. Deciding has initiative. Knowing has only awareness. You can decide that something is done when you hit five milestones on the Gannt chart or you can decide that it's done when your critical path is blocked or you can decide that you have more important things to do in your life than commit indie bands to vinyl but in all cases, you are making an active choice. But nobody can decide but you, and while you should absolutely solicit all the advice and counsel you need to make that decision, you should never give it over to someone else.
I know this won't apply to all or even maybe most of what you named here. As you may know I've been on a fitness kick lately and have been scaling up a fairly challenging and time-consuming routine. I do most exercises all on one day, the next is my rest day. It's very simple and I just keep that pattern going. The core exercises I have been doing are push-ups, jumping rope, some lunges, and run/walking. Sometimes I throw other random things on top for fun. Especially with the easiest quantifiable things (push-ups - count; run/walking when on a measured & marked track) my goal every exercise day is to simply do a little more, do a little better, than I did last time. If I could do 10 push-ups two days ago I figure I can manage 12 today, and so on. One day I ran 3x .75 miles (with breaks in between). The next day I ran I ran 2x 1.1 miles (with a break but shorter). I know that with all things there will be set-backs, plateaus, bad days, sick days, injuries, etc, and I also can't expect to continually do more push-ups each time, or always run further than I did last time. But for now in this phase, I know I am done an exercise or work-out portion for the day, when I have done more than I did last time. I don't allow myself to stop/take a break/"go easy" if I haven't achieved at least what I did last time. If I could do it last time without breaks, and I had a full rest day to recover, I can do it again. There are other angles to work improvement, too. Like upping the # of push-ups I do in a set, running faster, etc. I don't have a "done" or an "end goal" really. I want to be healthy, happy, busy, fit. And fitness is one of those forever projects, so hopefully, I'll never be done with it (as long as I'm alive). But I did want to chime in that the way I answer that question on a very literal day to day level is "When I have done more than I did before/when I have pushed myself harder than last time/when I have challenged myself (and hopefully won)."