How often does an un-neutered male cat spray?

My cat just turned 6 months old.I have an appt to get him neutered on monday. It is the earliest I could get him in. Yesterday he sprayed all over my suede loveseat. He hasn't sprayed before now. I actually have a few questions...How often do cats spray? If I let him outside (he stays inside all the time), will he spray out there rather than in my house?i have a small house so him just doing it once makes it really strong in here! how in the world can i clean my suede couch to get the smell out?its awful! Any advice you can give on this would help me greatly! I just need to make it to monday!