Over the years I have seen a few people lose their collection partially or entirely so quarentine is priority number one around here and only got stricter and stricter.
Any new animal is quarentined for at least 90 days in a room situated on a different floor than my snake room and at the opposite side of it.
The main snake room is also sealed of and therefore the air does not circulate from other room to this one.
New additions (one at the time unless it from the same breeder) are treated for mites regarless. When I get new additions I also treat my snake room for mites not the enclosures just the room (stairway, floors etc)
If I interact with my collection and QT animal I interact with my collection first and do not go back to the main snake room after dealing with QT animals.
I do not go to pet stores, and when I go to shows which I do 5 times a year or more I always undress wash cloth immidiately, shower and wash my hair and avoid my snake room until the following day.
I also only buy from a handful of breeders that are as paranoid as I am, I don't buy from Joe Schmoe on CL.
My collection is also now completely off limit no one is allowed in the snake room but me.
It might sound over killed but it has worked for me, I have work too hard to get my collection where it is now to take any risk.