The recommendation of using the tub for 5 times was based on the observed average age for the tub to become soiled or to lose it's structural integrity. The tub is not necessarily designed for permanent use, but is robust enough to expect that it can be refilled 5 times without any issue. If the tub is still viable for containing the wipes and has not become soiled or contaminated, then there is no reason why a consumer could not make the decision to continue to use the tub after it had been refilled 5 times.