Broken piston rings are usually the result of carbon buildup in the rings or a piece of carbon getting under a ring.  This prevents the ring from rotating during the compression stroke and thereby prevents the lubricating oil from coating the cylinder wall. As a result, the ring gets brittle and breaks and the cylinder wall gets scored allowing the piston to "freeze".  Hence the powerhead "blows".  The best way to prevent this is to use a "Kwickleen", "Seafoam", "Carbon Guard", or"Ringfree" product regularly in your fuel and decarb the engine annually.  Addtionally, you can run a full synthetic oil in your mixture such as Amsoil.    Full synthetic oils are carbon free since they are made with synthectic base stocks rather than petroleum.  There is virtually no carbon buildup with this type of oil. 
After doing all of this, there is still no guarantee that an engine will not freeze up, as there are several other reasons that could prevent oil from reaching the cylinder or rings.  But this method of operation is very good insurance against the most common cause of powerhead failure.

Smitty 8)

Yeah, but Glenn .......he wants to catch fish!..................he he he he he he.....