Persistence is the main attribute of long-term memory (LTM) and a strategy to improve it is to act on specific mechanisms several hours after learning. Here, we assessed the effects of spaced learning to promote memory persistence. Using a spatial object recognition (SOR) task in rats, we designed a protocol of 2 learning sessions. A weak SOR (wSOR) training session induced short-term but not LTM, whereas a strong SOR (sSOR) training session formed a 24 h-LTM which did not last 7 days. We found that a wSOR-retraining session performed 1 but not 7 days after a sSOR training promotes SOR-LTM persistence. However, this effect was not observed when the wSOR was replaced by a test session. Our results suggest that this promotion depends on the mechanism of sSOR-LTM expression induced during the second training, and that a reconsolidation process has not been involved. Based on the Behavioral Tagging hypothesis, we postulate that retraining will mainly retag the sites initially labeled by the prior training and the memory expression would provide the proteins needed to be used by the learning-tag in order to reinforce or stabilize the memory trace. Also, we studied whether a similar approach could be applied in elementary-school students, with the aim of improving teaching strategies. A first study using a geometrical-figure test showed a LTM enhancement in the group of students that received a second learning session (test or retraining) 2, 7 or 14 days after the first one.