There is really no need, unless you've particular goals.
If you're just looking to level Archeology, just pick a continent and stay there. Most people do EK exclusively, as that has the highest probability of Troll digsites for the coveted sword.
If you're going after the "Professor" title, you will need to see when you've achieved the 30 or so blue artifacts found on that continent, and move to another continent manually as each completes the sub-goal.
In short, it depends on the goals of why you're doing Archeology.
If leveling is your only goal, there is no compelling reason to change continents. You can get toon levels to 85, or 1-525 Archy levels all on the same continent. (Not sure to which 'level' you were referring. )