When you cross a poltiical line, county, state, province, territory, nation, etc. the laws and recordkeeping system may chance, in some cases significantly.
Even when crossing states/provincial lines, the laws regarding what is recorded and how it is recorded may change. Learn about the new area's records before you assume that Virginia in 1760 is just like Nebraska in 1860.
That's something of an extreme example, but it hopefully makes the point.