I have one fully researched tree 'gifted' to my by an aunt - containing hundreds/thousands - each personally researched, parish records consulted, everywhere visited in person, over 30 years. Most of it inaccessible to anybody who wasn't local and in two languages/three countries. It goes back to the 1300/1400s. Proper job.
Mine, that I've done "for free" contains about 150 people. But I'm 100% sure that 99% of it is spot on. But that just contains those I could find, not those I had to really 'research' as such. Oldest ones in there were born in about 1790-1800. Lazy bones effort
I'm stuck at finding out where these people who just "turned up and got married one day" came from, without father's names in PRs there's no clue. I went through an entire PR this morning, trying to tie them all together to try to nail any connection between anybody with the same name .... and ended up with a big chart of people who "just died there, without any other note", or "just married there, without any other note". My family are the main backbone of that parish record - having married there, they stayed and produced children there, who were baptised (allbeit with 3 spellings of their last name) and kept marrying/living there.... but where the first couple materialised from is still a mystery to be uncovered.
The tree goes back to my GGG-grandparents. At that point the man's upline stops. The female upline is still traceable back some more generations (quite easily).
So, overall, I grind to a halt about 1800 in most branches.
I'm sure when I do work it out I'll discover he's the son of William ..... because everybody else seems to be called William, or have married William ..... and called their sons William....