Does one really need a solid in their bag? I currently don't have, and I really wonder if I could get by just dulling up one of my pearls. This fall I am moving up from a Sub role to bowling at least every other week in one house one night a week.
For most leagues, especially in well-cared for houses, and for many bowlers, a solid is not a necessity. FOr other bowlers, and in some houses that are not well maintained, a solid can be a versatile tool.
While in many cases, a dulled pearl can substitute for a dulled solid or a dulled hybrid, in many other cases, a dulled pearl will NOT act like a dulled solid will NOT act like a dulled hybrid. The same is true of polished balls. While in some of the above cases, the ball reaction can be similar, in many other cases, the ball reaction will be anywhere from completely to slightly different.
Higher ball speed bowlers will often see much less difference than lower ball speed bowlers, especially when their rev rate gets to the medium range (~300 rpms) and above.