You don't need it and if you are on a limited budget you can get a good hard tail much cheaper than a good full suspension but if you have it you can stay in th

You don't need it and if you are on a limited budget you can get a good hard tail much cheaper than a good full suspension but if you have it you can stay in the saddle much more of the the time for efficient pedalling. It doesn't lose much of the pedalling power certainly if you spin the pedals rather than stand on the pedals in a higher gear.