The one area of genealogical research that I really enjoy is looking through census records. Anyone doing Scottish research is fortunate to have a rich resource of information contained within this particular area.
Scottish census records started being taken on a regular basis in 1801 but the most intact and more readily available are from 1841 through 1901. 1911 should be available sometime within the next couple of years. There was no national census taken in 1941 due to WWII.
There are a number of places you can go to look at census records. If you live in Scotland you have the options of Register House in Edinburgh, your local library, your local FHC, and some sheriff's offices. If there is down time some of the local registrars may give you access to their computers for about an hour. If you are looking from home you can access Register House through ScotlandsPeople, use Ancestry, CensusFinder to name but a few.
ScotlandsPeople gives a really good, concise breakdown of what kind of information is available in each census and what "date" each census was taken.
A word or two of warning :) Census records were only as good as the person providing the information and/or the person writing down the information e.g. a persons age or place of birth, how the enumerator heard an accent. They also were a snapshot for one particular night and on occasion people would go missing, show up in two different households or be in an entirely different household than normal.
When I started to do some serious research on my Lindsay ancestry I was in the fortunate position of having a partial family tree already in my possession and wouldn't you know it the main family line we are descended from turned out to be much bigger than indicated :)
My Lindsays are descended from William Lindsay and Euphemia Robertson. Our family tree shows their children Agnes, Jane and William(mine) with most of their descendents up until the 1970's. So I went rooting around and eventually found out that they had 4 more children who were all deceased by the 1851 census. Some of them showed up in the 1841 census BUT and this is a big BUT, it was in an extract someone else had written down and stupid me forgot to write down the on-line source. Aaargh. It did however help me look for, and find them in the OPR's. (More about that in another posting.)
It's so important to write down your sources because you never know when you may need them. Citing your sources makes your information more reliable not only to yourself but to others as well.
If there is ever a dispute amongst people you can say well this is a primary source and I got it from here. The more PRIMARY the source the better e.g. birth, christening, marriage, death, and sometimes census. Some people consider wills, land and military records primary but I put them as primary/secondary. I'll go into that in more detail in another posting.
So I followed William and his family through as many of the census records as I could (they moved around a lot). This helped me pin down time frames for births, deaths and shed some light on a few family mysteries. Every family has a mystery of some kind :) From there I was able to look at birth, marriage and death records within a shorter time span, which saves a considerable amount of time (and money) on many occasions.
The one mystery I have still not gotten pinned down is who are William Lindsay's parents? They are not named in his marriage record or his death record. His son, bless his kind heart, was pretty exact about his age when he died. I know where he was born even though there are some pretty funky spellings on the census records. At one point I travelled along a lengthy and unfortunately false road for him (there went 200 years of ancestors when that one came to a grinding halt) and looked at any number of OPR records in and around the Blairgowrie, Perthshire vicinity. I now have two possibilities, James Lindsay and Agnes Loban/Lobbins or his birth was not registered.
Another area that census records are useful for is researching a particular house, street, town etc. The house I grew up in was built about 1883 and on my last trip to Scotland I did a street/house search at the local library. That was fun. I learned a lot about the street name changes that happened, who the neighbors were etc. I also bought a copy of a very old map that showed who all lived in the houses round the castle and town center. I also ran across some old photographs for the area. I looooove libraries :)