Expo has been programmed into your transmitter because its useful. SO use it as much as you need. Its a personal preference. It cracks me up when people pride themselves in using no expo but fly with tons of other mixes and multiple rates. Its a tool use it to make your flying easier and more enjoyable.

That being said too much expo makes a plane respond sluggishly. So just ease it in till it feels good, then once you go too far take some of the expo back out until you hit the sweet spot. Someone here gave me some good advice the other day regarding this. On high rates add enough expo so that right around the middle(neutral) you cant feel the difference between high and low rate flight characteristics that way when you are coming out of a spin and forget to switch to low rate you dont accidentally pull too hard and snap the plane. Lets face it when you have a rate set with 45-60 degrees of throw you intend on using all of it most of the time or you wouldnt be there,,, specifically on elevator. So add in a ton of expo on extreme high rates so that its gentle in the middle and soft for recovery but still gives you max throw for walls, elevators and waterfalls. ....