Deck and Fence staining and painting is dry weather work. We only use high quality products when completing this work, both vertical and horizontal products are available, we usually try to stick with 3-5 colours. A newly completed deck is only going to last 1 year if exposed, if it's under cover and treated well it should last several years. This work is not guaranteed as there are far too many variables and there is no way of knowing what type of traffic it will be exposed to. A newly stained fence should last up to 5-8 years, however, the top will start to fail sooner due to being horizontal.
Transparent stains will usually repel after a one coat application, therefore, in many cases you should only apply one coat. There is also less uv protection with transparent products. A solid or semi solid stain will be more durable than a transparent or a semi transparent stain. You can usually apply 2 coats with a semi solid product and 2 coats or more if needed, with a solid stain.