Recent metaheuristic developments have proved to be successful especially in cases where their fundamental concepts are complemented with pool-oriented approaches such as scatter search. These algorithms maintain a reference set of high quality solutions which are repeatedly used during the search in order to guarantee a fruitful balance between diversification and intensification. However, maintaining such a pool is not a trivial undertaking. The main problem is to find a balance between the attempt to collect a number of high quality solutions, which often results in similar solution properties, and the need to guarantee a certain degree of diversity in the pool. In the present study we highlight the advantage of pool-oriented design while focusing on controlled input and output operations. We analyze the main pool components for metaheuristics and present a review of the literature on relevant strategies in tabu search, scatter search, and path relinking. Additionally, we provide a synthesis of the literature that highlights the critical aspects of effective pool maintenance.