How to Construct a Legally Defensible Record of Genealogy
When you construct your family tree (or someone else's), the legal system requires "concrete evidence" (more on this later) that you have identified the correct people. Otherwise, you could be going down the wrong path through someone elses family.
There are few things in public records that are more important than finding records for each and every person that you want to add to your family tree as you go back through time. You may want to see how far you can go back, but you should never do that at the expense of not being sure you have the right people. What would happen if you put years into your research only to find that you went the wrong way? You would have wasted all of that time. Make sure you find vital records so you are sure before you move on.
The vital records that you can find about most people that you want to add to your family tree are out there somewhere if you know where to look. These include records of marriage and divorce, birth and death, and a few other things in some cases. In some cases, where public records were destroyed in floods or fires or lost forever, but most people can find the vital records that they need for their family. They name people in the past, and verify they are indeed in your family.
Public records for those that are still alive are very hard to find. Some sites that deal with genealogy records will not list vital stats and records for other reasons. When someone is still living, you can get your information elsewhere anyway. The records you find through these sites are going to be for the members of your family that have passed on. Along with vital records, you may find things like property deeds and immigration records that can help support or dismiss your claim.
You can decide for yourself (I would, if I were you — but then, I have no money problems — not anymore) if you want to pay for a membership through some of the bigger sites, or rely on what you can find through the public sites. The ones that have no membership fee are that way for a reason. Most of them have somewhat-accurate information, but not accurate enough to support a claim of family heritage in a court of law. So, it depends on what you hope to accomplish.
If you are willing to tell yourself that you must find my family's vital records, but you dont have a lot of time to search, you can always find new clues through a source that can give you what you need in due time. Sometimes, this can come up in minutes if you can pay their research fees.