Anything that has to lock and stay dry between jobs.
What to look at first
Start with the weight of the thing you are loading, then add everything that travels with it: attachments, fuel, ballast, tools, straps. That total is your payload. Your payload plus the trailer’s own empty weight has to sit under the trailer’s GVWR, and the loaded figure also has to sit under what your tow vehicle and hitch are rated for.
For this kind of load we would generally start looking at 3,000 lb GVWR and work up. That is a starting point, not a rule: a heavier machine or a longer deck moves it quickly.