I think about how much money I have this month vs how many ponies I bought that month. I'm tight on cash due to bad work hours, so I tell myself if I buy a pony it has to be something I absolutely cannot pick up again!
Although yesterday I was super close to picking up my first MH doll until I realized how much money it would take out of my meager monthly budget. I just told myself I didn't need a new collection until I got money.