Overwatering of succulents can cause the succulents to shrivel up and die.
The overwatering of the succulents can also cause the succulents to suffer root rot which also can cause the death of the succulents.
The way to tell if you're overwatering your succulents is to look at the succulent plant and look for puffy-looking stems or leaves.
If you notice puffy looking stems or leaves on the succulent plants then you're overwatering the succulents and should cut back on the watering.
You can usually just water the succulents until the soil becomes wet and then as the soil gets dry then it's time to water the succulents again.