Recently I have been able to solve two pre-1850 research problems using tax lists in Virginia. If you're not familiar with them, I would encourage you to give them a try.
Tax lists can help you link fathers, and sometimes mothers, to sons. Tax lists generally contain a list of every male, usually over the age of 21. These are the men who had to pay a poll tax. If the male was younger than the taxable age but over 16 then his father, or widowed mother, paid his poll tax but his name might not have been listed. By tracking all the males of your surname over various tax years you can tell when there were males in the household over 16 and when they came of age or moved out on their own and begin to pay their own taxes.
Often relatives went to pay their taxes on the same day and so keep track of the dates they paid taxes if given. You may also find several men of the same surname listed next to each other on the tax list giving you an indication that they probably paid their taxes together when no date was given.
Sometimes on rare occasions the tax list will give the father's name AND the names of his sons for whom he is paying a poll tax, but this is not very common. Another clue to look for, when given, is the names of the slaves that the owner is paying taxes on. Sometimes you can track a slave with an unusual name from a father to a son in the tax lists.
You may also want to track their acreage and the location of their land if given. This is more common in Kentucky tax lists.
For more information I suggest the following article from the Library of Virginia.
Using Personal Property Tax Records in the Archives at the Library of Virginia