UV protection and water beading should last for a couple months after one application, but yes, this product can be layered, however there is no cure time like the Liquid Wax. This product instantly bonds so just wait 10-15 minutes and you should be okay to apply another layer.
This can be used as often or as sparingly as you'd like. Our customers use it often because only a very small amount is required, 1 spray per 2' x 2' section, and because of how super quick and easy it is to apply.