ITA. Use it when ever you want to. I like it or Nexxus Ensure because its a thin conditioner so I use it after working out. (they both do the same thing so sometimes I go cheap and get PC )
I was in a beauty supply store once when this woman recommended it to me. So I brought the shampoo and conditioner on a whim. I LOVED this stuff! I used it as my sole shampoo and conditioner for at least 5 years (while relaxed) and my hair loved it. It was a thinner consistency than I was used to but the conditioner was the best I had ever used (it's a thicker formula now than when I first started using it years ago).
Well, I went natural and at first I kept using it (it still worked great, but not quite as well as when I was relaxed). I was curious to see if there were products that would work better for my natural hair (I also threw/gave away a lot of my products I'd used on my relaxed hair). But, after trying a lot of different shampoos and conditioners over the last 7 months I've decided to go back to using porosity control.
I had a little bit left (enough for one wash & condition session) and used it to wash my hair the other day. I wonder why I ever abandoned it. For me, it cleans my hair without overdrying and the conditioner leaves my hair really soft without being coated. It even works well in the hard water I have at school (I have soft water at home--so I've had the chance to compare).
Verdict? Two thumbs up!
ETA: I used it weekly. Just like any regular shampoo and conditioner.