That is totally up to you. The terrova sits forward on the boat and some people have issues with it hitting the toilet putting the boat on our talking it off the trailer. Some just don't want it to overhang the boat when ting to docks. Mine never had an issue so I didn't need one. I did end up installing a sliding mount to make the cover for better.
Personally, I think that I'd rather buy one of the sliding mounts. You can remove your trolling motor easily from the boat with one of those also if you care about that. Basically, you just pull a pin and slide the motor forward them put the pin back in to lock it in that position. The lift saver looks like you have to lift the motor and rock it forward every time. I wouldn't want to have to bend over and lift it any more than I have to in a day. You are already going to be lifting to deploy and store it every time that you use the trolling motor because there is no pull cable.