Using timelines can help you see a family in the context of itself and history and timelines can help you assure accuracy by sorting out families that have similar names and dates. There are personal timelines for individuals, family timelines for a nuclear family and historical timelines that show the individual or family within the context of local, national and world history.
An individual timeline starts with a person’s birth and ends with their burial or completion of their probate. It shows births of younger siblings, his marriages, births of their children, and deaths of primary family members such as parents, siblings, spouses and children. You can make it as detailed as you want it to be.
A nuclear family timeline starts with a couple and contains information on all of their children and can be extended to the grandchildren without too much confusion. You can see that an individual timeline will turn into a nuclear family timeline when they marry.
Historical timelines place the births, marriages and deaths along a timeline of local, national or world events. Knowing that when your great-grandparents were children several major Civil War battles were fought on their farmland and that they were actually in enemy territory after these battles helps us to understand or imagine what life was like for them. Historical timelines can also indicate other wars or events that may have affected the history of your family such as the California Gold Rush and the acquisition of the Alaska territory in 1863.
In my pedigree, there are several men named William Brooks. Two of them married women with the name of Mary, one married an Ann and the rest married Elizabeths. By doing a nuclear timeline for each family and adding records like land, tax and probate I was able to sort them all out.
There are many ways to do timelines and these are some excellent articles on the subject: