Systems, methods, and other embodiments associated with selectively acquiring and utilizing query statistics are described. One example method includes selectively acquiring statistics associated with search queries submitted to a search process during a sample period. The statistics may be associated with an index and tokens associated with the index and search queries. The method may also include selecting tokens and/or queries to optimize based, at least in part, on the statistics. In one example, whether and/or how the tokens and/or queries are optimized may depend on estimating index fragmentation based, at least in part, on the statistics.