I've certainly completed the thing that I began in 2007, which was an Excel-based pedigree chart for myself, going back five generations (i.e. to 3xgt-grandparents). Yes, it began as pure name collection (with BMD dates), but my preference is always to get a structural framework in place before filling in the detail.
Then life got in the way and I put it to one side. Didn't really get back into it again till late 2016. Since when I've gone back a further generation (64 4xgts), mostly now complete.
My ancestors generally lived uncomplicated lives They were diligent when it came to baptisms, registration, and so on. Overwhelmingly English. It has been easier than I expected, though the online resources are more numerous and plentiful these days. I'm always open to feedback, but generally I think I'm quite a careful researcher and I'm at least 90% confident (maybe 95) in what I've put together.
One of the key things I think that many people learn as they get older is the extent of how little they know. Certainly true for me with family history. So much more to be done. But any endless hobby (e.g. gardening) needs milestones to mark the progress/process of the ebbs and flows. So I have finished what I started.
And then I've started again
Further back, further sideways, more detail, further forward to living relatives, further into the social history surrounding the trades, the faiths, the political events that were the backdrops to their lives, the disease epidemics that claimed so many of them, emigration and American history. Then when my nieces/nephews show any interest I start looking at families-in-law and then in-laws of in-laws. It just goes on and on.
This aspect will never finish, but I do think it's helpful to set yourself specific objectives so you can 'complete' something every so often.
