I have a 2005 Ford Taurus and the horn stopped working a month ago. I ended up replacing it with a factory OEM one. It then worked until last night and now it's dead again. It's only been a month. Do I presume this to be a defective part or something else going on like a short or voltage issue or should I just replace with another one and see what happens.

Thank you in advance to any suggestions here..

 

It is usually better to confirm good voltage supply and ground connections before replacing a horn that won't work. If those conditions are acceptable then replacing the horn itself should solve the problem.
Possible places for a problem could be the horn pad contacts on the steering wheel, the horn relay and of course where the horn is physically located.
(A lot depends on where the replacement horn was manufactured)