I used to own my own trailer and the more it sat the more it cost me to get going when I needed it. Like tires they flat spot and dry rot. Also the inside and outside and wiring. We got animals bee's and other animals the used to make a home out of our trailer and eat the wires and padding inside of the trailer. So I thought of selling my trailer every two years and trying to not loose to much, but lost my shirt on that.
I then rented some horse trailers from those cheep rental yards well you get what you pay for. Some rental places don't know what a horse trailer really is and that I want to take care of my horse not drag it down the road. They don't care about your horse they will rent their horse trailers out for anything from dirt to piano's. So sometimes their are a lot of sharp objects in some.
So I learned a lesson since we don't use a trailer to much don't purchase one unless you have a nice place to put it and use it to keep the tires from getting flat spotted and dry rot.
It is less expensive just to rent a trailer if you are going to use it one in awhile than to own one. I rather put my money into horse feed, a new saddle, fly spray and everything else.
Owning a horse trailer is like owning a boat you love it the first day and the last day when you sell it.