Many employers grant wage increases at annual or semi-annual reviews. Some workers may not stay employed long enough to receive an increase—particularly if they become aware of a slightly higher wage available elsewhere. This can result in higher turnover and the loss of workers you want to keep. The motivational power of a pay increase is much stronger if the increase comes close in time to the performance you want to incentivize.
Consider offering smaller wage increases in shorter intervals so that solid performance is rewarded quickly. These smaller wage increases, or one-time bonuses can be used to reward acquisition of new skills as well. Rolling opportunities for wage increases makes it possible to more immediately reward the performance you want, increases worker engagement, and can help reduce turnover.