After 25yrs clipped I thought I’d try flats on my messing about in the woods bike. I tried it for a couple of months, deffinetly needed more energy climbing (a lap of Cwmcarn killed me), on slow technical climbs I’d lift my foot of the pedal if the rear wheel got hung up. After so many years of my feet being in exactly the same position clipped in, I felt uncomfortable with my feet being even a couple of MM away from that “sweet spot”. I did like the bit of confidence I got on slow steep stuff. But then I pulled my calf on a small jump because my foot was to far back on the pedal, so the spd’s went back on and I couldn’t be happier