I first started researching my family tree a few years after my mother's and father's death in 1991/1992 after realising that the family was getting smaller and that there weren't many people I could relate to about the family history.
I felt that for the sake of my children and prospective grandchildren I had to put down on paper as much information about their ancestors that I could find.
I find that some 10 years down the line I'm still finding out things about the extended family e.g. occupations, when and where they lived, parentage etc. and this is what keeps me hooked on genealogy.