You use it whenever you are looking to aid fat loss, so if you are looking for fat loss on off days then use it. The main thing is that Albuterol will become less effective over time. You will have to ramp up the dose, and you should take at least a 4 week break after 4 weeks on in my opinion to keep it working.
I'm into my second week of AGguys albuterol, and I'm upping the dosage to 18mg a day already. I thought it may be stronger or I'm just not stimulate sensitive. Hoping for better results this week. If not i will up to 24mg in the third week. A little disappointed so far so hopefully it gets better. The main side effect I'm getting is head spins every now and then and a little shakey when having a coffee.