Timelines are a very useful and probably underused research tool. By simply listing everything you know about an ancestor in chronological order you can see time periods that need work, dates that can't possibly be correct or things that just don't seem likely when compared to other events. Including historic events from an ancestor's lifetime can give you a much better perspective on their life. I might not have realized on my own that Thomas Jefferson was President of the United States when John Covey was born or that he was 42 years old when gold was discovered at Sutter's Mill in California and 59 when President Lincoln was assassinated.
Most genealogy software can create a chronology report. I created this report with Legacy Family Tree. Legacy has some preset timelines that can be used and also allows you to add your own. For this report I used their US Wars and US Presidents timelines and added a new timeline of historic events using the website Infoplease to find events I thought were interesting. Legacy creates the Chronology as part of an Individual Report in PDF format. Below is the first page of the chronology but you can see the entire report here.
In addition to genealogy software programs, there are other programs around that can create timelines. The report below was created using Genelines. It has a different look and fits everything on one page. The PDF version here is easier to read than the clip below.
Disclaimer: I have no interest in and nothing to gain from either Legacy Family Tree or Genelines.