Who is to tell you whether or not you should quarantine? It is ultimately going to be your decision. If you don't want to do it, then don't. The quarantine police won't come knocking on your door. Just know that you still put your established collection at risk. If you are willing to take that risk, that is completely at your discretion.
I will admit I don't have the best quarantine procedure, mainly because I don't have the space to do so. I will also admit that there are a few specific animals I did not quarantine. Should I have? yeah probably. Are my snakes all dead? Nope. I personally quarantine for mites, RIs, parasites.. anything that shows up in under 3 months. Scary diseases and viruses that wipe out entire collections are, in my opinion, extremely difficult to quarantine. With my current procedures, I would not be able to stop something like that.
If I got something through the mail, I would quarantine it. Plain and simple.
If you are asking, it means you are unsure. We can only give you our opinions, it is up to you to follow through if you so choose.