Oh boy ... I had this problem during the Source-a-thon. (If youcan call it a problem?)
There I was, finding an Unsourced profile and started searching diligently for a source.
Then I fell down a rabbit hole and found 9-10 sources - birth, censuses, death, Find a Grave.
Only to find while I was rabidly source hunting that someone else zoomed by, added one little source, grabbed the credit/point for the Source-a-thon and zoomed away.
At that point I usually just added what I had found out additionally and moved on. But from then on I was sure to add one source initially, save tog et the "point" for the contest and /then/ go on my rabid source search. But I certainly didn't get as many points as the rest because of it.
More recently I "volunteered" to do the family tree for my step mother because I had exhausted the "easy"/low-hanging fruits on my own family tree and felt like doing more tree research. Now my step mother could care less about this stuff - she usually starts getting glaze-eyed when I told her all about the stuff I had found out about my ancestors and I doubted she'd feel any different about her own ancestors. But still ... I've been happily building out her tree, getting tons of resources. I even managed to connect her to an ancestor that would technically allow her to get membership to Daughters of the American Revolution. Plus a Mayflower ancestor, to boot! (Something I do not even have on my own tree!)
She still doesn't really have any interest. Heh.
And, off-topic, but I've found out through all this process that I dislike doing research in New York state records. The marriage indexes online do not list the name of the bride/groom's parents and I've no idea if they do on the actual record or not. (Plus having to provide proof of death, it seems, to get a genealogy copy of a marriage record of people born in 1890 that are most obviously dead by now.)
I'm thinking maybe I ought to try some other challenge besides Source-a-thon since that seems to be keyed more at just "one source and run" type deals and I like doing the whole she-bang.