When researching for your Scottish Ancestors, it is important to know the parish they lived in as well as the neighbouring parishes. Remember, prior to the industrial revolution and the mass production of planes trains and automobiles, transport was primarily by horse.What this means for you as a researcher is that your ancestors didn't wander very far if and when they moved. Movement would primarily have revolved around employment opportunities, so you need to know where the jobs were. For instance, my coalminer ancestors worked for whatever colliers were hiring. They would have been within maybe a 10 -20 mile radius of where they grew up. Fishermen are going to follow the sea - so they will stay along coastal regions. Shipbuilders stayed near the Clyde (Glasgow) and weavers stayed near the looms and mills - often around the Borders.
It was very uncommon for people to move a great distance, apart from the Clearances, when islanders moved to the mainland. Even when women married, they generally didn't go very far.
My miners came from Shotts - the lower half of Shotts Parish. They mined in Shotts and Bothwell with one branch of the family making it as far as Hamilton. The farmers were in New Monkland and ended up in Shotts. Not terribly far from where they started out. Have a look at YOUR parish and really get to know the area your ancestors came from. This will also let you rule out some families in the records who may have the same name, but who were many counties apart.