We've all had great hopes of placing our ancestors in an earlier generation by using wills and probate proceedings. Unfortunately, too often some hazy terms are used such as "his wife," or "his children." Sometimes, however, we are surprised by the amount of detail that's been meticulously added. Here is an example from Van Buren County, Iowa, and the estate of my ancestor, George Channell, who died in 1898. Note that every heir is named, along with relationship, residence and age. It isn't as though these are young children, either. This is an excellent means of confirming information I'd collected from other sources.
A further example of the benefit of collecting ALL available data, not just listings out of indexes or abstracts. This comes via microfilmed copies available via the Family History Library. I viewed them in Salt Lake City, but the film can be ordered online for viewing at local Family History Centers.