Certified GKH Gardening Expert
You should water a Yucca once every 10 days.
When the soil is dry down to a depth of about an inch or two.
Being native to the southwest, Yucca plants only need water when the soil is completely dry a few inches down. They need soil that drains well, and will tolerate a really good soaking that mimics natural rainfall when you do water them. This article will give you some tips on caring for yuccas outdoors: https://www.gardeningknowhow.com/ornamental/foliage/yucca/caring-for-and-landscaping-with-yuccas-outdoors.htm