Like they said, they only add value to your enjoyment. When you go to sell, the lift will be seen as an excuse to say you abused it going off roading, like a super charged car was abused with speed, etc, etc, etc.
Sometimes it can work out, if you keep all your recipients and you have a lawn full of vehicles in great shape to prove you are a car lover and take care of them. Yes, your Jeep has dings and scratches from lovingly taking her offroad, as thats what yer supposed to to, the lift was installed right, as was the electric fan and switch to turn it off when fording a stream, etc. The right person may be willing to pay what you've put into it, but it almost NEVER happens, which is why sports cars and toys are called money pits. You never get out what you put in... Unless its a '71 Stingray, lol, thats a solid investment