It depends how information is available about your relatives
in archives. There can be plenty, there can be little.  People in archives won’t overcharge you if they can’t find plenty of

Professional people working in archives will fetch
most archive documents about your relative – if he every served in
military. If he went to court or election. If he purchased
something. If he had some contracts. All his documented activity. Not just a regular church
record when he was born, baptised and who were his parents and God
parents. Some people were lucky to get records of their relatives to
early 1400s. I know my ancestry from mid 19th century.