I use all mine, though I only have 5. LPF is always on, though it's not used as an envelope filter for funk wah type sounds all that often. I now wouldn't be without the 5 that I have (Octaver, Bass Murf, Distortion, Chorus & LPF with exp pedal).
It does depend on the type of music you play. For a rock band, you could get away with just 1 or 2 fx at most, but if you play electronica type stuff (such as DnB, Dubstep, House & so on) you'll find that effects become a staple part of your sound.
I play in a folk band.