Tracing my Family Tree has certainly been something of a 'quest'! Genealogy seems to involve a certain amount of sleuthing - it's very easy to find you're following the 'wrong' line and I also have little pockets of family relationships that seem to tie in if only I could find definite links. It's a bit like doing a jigsaw puzzle - you find people that fit together as families, but until you can definitely link them in with 'proof' documentation you can never be sure they are the right 'John/Jane Smith'!
Census returns are invaluable in tracing the members of a family and their movements - a ten-year gap can introduce 'new' members of the household, as well as their geographical changes.
Then there are the 'quirks'! Genealogy is not an exact science (oh, that it were!) so you need to have a certain amount of flexibility - backing up your 'theory' with as much evidence as possible is vital. When I used to work in our local library, a lot of people enquiring about Family History were ushered my way (the other staff knew I had a keen interest!) so I spent a fair amount of time in the Local History section. It was lovely to see people trying to identifying their roots, but it was also difficult explaining exactly why Great Aunt Matilda wasn't on the census returns, or even that the age was 'wrong'! As I've said before, don't believe all you see - the accuracy of even official documents is dependent on who wrote them (and what they were told to write!)
I once spent months assuming a mother and child in a family I was tracing had possibly died as they did not appear on a subsequent census return. Then, lo and behold, they popped up on a later one! A bit of sleuthing uncovered the fact that they had been visiting friends in another district on census night and therefore had not appeared with husband/father and the rest of their family. (I'd thought it odd that in the absence of a spouse the father had appeared as 'married' rather than 'widowed'!)
So, polish up your magnifying glass and adopt Sherlock Holmes-style sleuthing skills - you'll need them, to track down the missing branches in your family tree!