but was wondering how long did it take for you all to secure a hangar for your airplane?
I was on the list for about a year and a half at KGIF, but as others have said it varies with location. You might inquire about turnover rate when you talk to the airport. I know that on my row, a half dozen hangars have changed occupants over the last couple of years. One of the new tenants only had to wait about 6 months, so things change.
In general, do I need to own an aircraft to rent a hangar? Or can I get on the list before having an airplane?
At our place, you can get on the list but you can't sign the lease without having a plane.
When my name first came to the top of the list, I didn't yet have a plane so I wasn't eligible for the hangar. The nice lady left me in my place on the list, and just started calling down the list until she reached someone with a plane ready to move in. From then on, I continued to get calls every few months about an available hangar until I finally had a plane.
When I got "THE" call, my plane was under contract but not closed yet. She held the hangar for me for a couple of weeks, and by that time I owned it and had a bill of sale and a temporary registration. I had to show those, since the plane was still in annual inspection at the seller's location, and they let me sign the lease. It was a few months before I was able to bring my bird home.
There were several when I took over my position, but I terminated their leases and now require yearly copies of annual inspections for their stored aircraft. It is no longer a problem at my airport.
Similar here. They started doing annual inspections and have cleaned up a bunch of the "storage unit" problem. There are still hangars with cars or boats, but the ones I've seen also have some flavor of aircraft, like a trike or small LSA, tucked into a corner. One hangar had a couple of powered parachutes for a while, and I don't know whether the airport decided that wasn't sufficient or whether the tenant just moved.