well it's certainly thrifty. but no it's not hygienic. menstrual pads should be changed every few hours depending on how heavy the flow is. even on a light day a pad should be changed a couple of times. a pad does not have to be completely saturated before changing. when a pad gets moderately saturated it should be changed. if you can smell it it should be changed. your wife should not hesitate to change her pad frequently. she'll feel fresher and it's simply more sanitary. hope this helps!
my wife uses 1 pad the entire week she is menstruating. is this normal or unhealthy?