tips for gaining the most out of your patterns? Sewing Machines Parts and Sales in Los Angeles

Hey guys, I dont know if anyone else ever goes through this internal battle, but I DO!

I buy a new sewing pattern, bring it home, get excited to start, and I just cannot take my scissors to the pattern. “what if I need a different size in the future?” is the main question that pops in my mind and prevents me from starting projects.

My question is, is there a way to use ALL the sizes of a sewing pattern instead of just one? Does that make sense? I want to be able to reproduce an item in many sizes over and over again; not just one size, one time.