When i started with MAC it was about once a week. But now that I have a nice solid collection (way more e/s than lip stuff though) i just go for the new collections and when i need more basics.
I'm still building up my basics (as my wallet screams and trys to run far far away) so I'm budgeting myself right now. But when the new collecs come out I pick up what I like since it's LE and I'm only usually interested in 1 or 2 items.
I started getting into MAC a lot around when the Barbie collection came out. I spend about 75 bucks a month on it now. I feel around I round out my collection than I won't buy as much. But for now I am a junky.
I have slowed down my MAC buying recently. I first started getting into mac last november since then I buy about 60-100 on MAC each month. I need more brushes so I think that is gonna go up.
I will purchase something maybe once every month or two. I tend to stay away unless I run out of something or a new collection comes out. I just don't need that much stuff!
Recently I would say that I making significant purchases once every 4-6 weeks with multiple small purchases within the month. Hopefully it will slow down after the Fall collections! Argh!
Usually spend about $50-$100 per month.
Spent alot during the Barbie Collection & had been buying backups since.. now trying to control my spending until the next special packaging LE coming out..