The satisfaction in this hobby is that you do your own research. Sometimes other peoples is useful and thats a bonus..and you can add to theirs. Also how far you want to go? Why build trees of 5000 people, whats the point in that? Its like having 5000 friends on facebook. Daft, its a bit ASD. Id rather build a new tree for someone else..and get it right!
Further. Its an absolute no no to put living people into publically viewable family trees posted on to genealogy sites, in many cases they wont know they are on there or even know you if you put them there. Wrong. Its also very easy for people to extend those trees into tracing living relatives by using GRO indexes and free BMD and then People Finding Services and Social Media.
I have roughly 6500 people on mine. I can honestly say that any mistakes in there are not due to me not caring, not try or not applying due diligence. I am researching both my line and the paternal lines of both my daughters. I am working through each generation now and finding the siblings in each generation. I am doing this as, to me, how many children and siblings my ancestors had are part of their life and this hobby to me is finding out about their lives as well as their names. I have also sought deaths, marriages and children for each of them where appropriate. This is very much a work in progress and I have never claimed it to be anything but. I am also fascinated by how diverse the descendants of one couple can be.
I have also found that researching siblings can help solve mysteries for my direct ancestors. For example, my 4x grt grandmother was widowed and left struggling as they had lived in a tied house. Then next census she is living in a nice cottage as an annuitant. Mystery solved in researching my 4x grt uncle. She was awarded his army pension when he was killed in Afghanistan and awarded a posthumous medal. Then there was my 3x Grt Grandfather Pratt, on all census returns born in England, no specifics. One of my 3x grt uncles (his son) was born in 1855 which meant his birth certificate gave his parents' places of birth. I am confident he was my 3x grt uncle and not someone else with the same surname because his name and age fitted with the census, I had births for 3 other siblings matching the census and their parents' place and date of marriage matched. My grt grt grandfather was born pre 1855 but the parents names (including middle names) match those listed on my grt grt grandfather's marriage and death certificates. Additionally the address on the census closest to the marriage matched the address from which he got married.
A good number of these 6500 people are the in-laws of my aunts and uncles (and great, great great and so on). The majority of my family lived in Scotland so all the post 1855 marriage records have both parents of the bride and groom named where known. I always record all the details on the marriage certificates and record on my tree that these are the parents according to the marriage. I do not research them any further as they are not my blood relatives and I am well aware that people did lie or had wrong information themselves. I don't see and issue with this as I record that these are the parents according to the marriage certificate. For me it helps identify for example which John Smith Great Auntie Mary married.
Here's an illustration of how the numbers add up. I have myself, children and 1st and 2nd husbands on my tree making 5 people, parents for the 3 adults making
11, 6 siblings my generation making
17, 5 of them married making
32 (because parents were noted). Then 35 siblings in parents generation making
67, 32 marriages between them
124, 84 children between them making
208. I'm sure you get the picture. I have either the birth record or a photocopy of the birth for all of them and marriage and death certificates where relevant.
I cannot tell you how many sources I have as I had never counted. I started making a comprehansive list of all my sources a couple of days ago and it will take some time I am only up to source 92. What I can categorically say is not one of my references is a tree from Ancestry, family search or similar. I do have a couple of entries in published pedigrees for people in my tree who were awarded titles but none of those is the sole source for the data they evidence. I work on the premise that there is no such thing as too much evidence while keeping in mind that there may be very limited surviving evidence for some people. My sources include: birth, death and marriage certificates; 1939 register, census returns (1841-1911), parish records of baptism, marriage and burial, newspaper obituaries, birth, engagement and marriage annoucements, Indian medical service employee records, wills, probate callander entries, funeral invitation cards, historic undertaker itemised receipts, university admissions records, university graduation records, family letters (from as far back as 1790s), monumetal inscriptions, CWGC entries, service returns, land registry entries, newspaper stories about events my ancestors were involved in, invitations that had been maintained by family family bible (completely cross referenced with BDM records), court transcripts. This is not exhaustive this is just what I can remember off the top of my head.