buying a used inspire isn't a bad idea to save 1000 bucks and i would think by now replacing hardware parts can be done by people other than the factory, even yourself. there is one major catch. if the software glitches out your f'ed. DJI has fixing software glitches on lock down and to my knowledge there is no way for a owner to factory reset anything to fix it.
if you can get a copy of the original recipe and the original owners name you might be able to pose as the original buyer and send it in for dji to fix under warranty. if not then your S.O.L. because dji are the only people who can fix software glitches with the remote, batteries and air craft. under normal circumstances your going to get stuck with the bill paying dji to fixed a inspire you bought used because you need proof of purchase new when you send it in.
your risk is the price of the used inspire plus the cost of paying DJI (the only people who can fix the inspire) adding up to more than then what it would be just buying a new one. i dont know what they charge when the problem isn't covered but i would guess you would pass the break even point pretty quickly with something simple(everything about the inspire is over priced)
if there are people out there that have found a way to break into dji's app software and factory reset the hardware please pm me with their contact info so i can turn off those no-fly zones that kick in 100 miles from anything in the middle of no where.
my point is while the thing is operating normally buying a used inspire is great, but once something goes bad software or hardware(and i would say there is a 50/50 chance this will happen eventually) you either have to deal with dji and play their game or roll the the dice with some stranger in his basement you trust with a 2000 dollar aircraft who found a way to hack the software.
maybe at some point when the
i2 comes out dji will chillax on the inspire 1 and open it up for owners to fix problems their selves. as it gets old it will get cheaper. if you can preserve a used i1 till that day then yes you could save some bucks.