I lived without a garage/enclosure on a lake where horrible wind, floods, bugs, rain, "nature crud," and spiders ruined and weathered everything. I looked online for enclosures and small buildings that would also be convenient to ride in and out of frequently. Many sealed hard plastic motorcycle enclosures were $2/3k+ and sold overseas. A zipper bag enclosure/bubble would get absolutely shredded by wind and water where I lived. I finally considered getting a small and cheaper trailer with multiple use cases! It cost me around $3600 but is also incredibly useful for many other uses as well (moving, transporting large objects, etc). I installed rubberized flooring and a condor wheel chock inside as well. The large door helps me easily ride in and out with a convenient side door for working on the bike. Even a year later, the inside has remained completely "sterile." No bugs and is dry with low humidity. Consider an option like this if you don't have space for a new building, don't have a garage, or would have use for a trailer to begin with.
edit: as discussed below, always consider the level of crime in your community to determine whether or not something like this would work for you.
