Are you by chance keeping the key in cold conditions? Like a non-heated garage? If the battery is constantly in a cold environment, it'll quickly kill it... Could be the cause?
No, the fob's kept indoors ... though I suspect cold temps might be contributory. Why would anyone keep the key in a garage with the bike though?
The trouble with that is it will cost you between £250-400 for the privilege, that's a lot of batteries to make it cost effective
Indeed, I'm more thinking if the key is dead every few months, it could be a physical fault and Ducati might be open to just replacing it FOC.
Which battery brand are you using. I always went for Duracell in the past but have found that Energiser seem to last longer in my experience.
I found the latest generation Duracell coin battery didn’t work at all in my remote so now only buy the Energiser version. Andy