Don't assume your ancestor moved infrequently. Some people did move rarely and others moved every few years. It might have just been your ancestor's wanderlust that kept him or her moving constantly. Or it could have been the local law, too.
Seriously--a relative of mine whose Civil War pension file I have appears to have moved at least a dozen times between 1850 and 1890. And she very well could have moved a few more that simply were not documented in the file.