When someone asks how long a job will take, I don't just blurt out a hopeful number anymore. I walk through the parts I can't see yet and add room for them. My boss noticed that lately, when I say two weeks, it actually takes two weeks.
More people experience this than they realize.
You want to give honest timelines that leave room for the surprises you can't see yet.
If this sounds familiar, the Library can help you find the bigger picture.