I for one love to read historical documents and primary sources. I'm glad some people in ancient times had the foresight to record a bit of their lives in the hope that future generations might find it interesting.
I’ve always found personal accounts and memoirs to be the best kind of writing. You get to read beneath the surface between the person they were, the person they wanted to be and the worldly circumstances they found themselves in.
You always have the option of committing your memoirs to stone, absorbing the long-term cost up front yourself.
Of course, go far back enough (I'm not sure if 500 years is enough) and mathematically speaking, the number of your ancestors will exceed the population of the world, which shows some other issues that you run into.