In addition to what has been said (pvcs is one of the perfect materials to work with...) I run failsafes on every set up reguardless if it is a new herpstat or not everything can fail the added safety is worth the cost. I clean thourly and regularly as a part (and by necessity how do you clean a rack with out removing the heat tape) all heating and lighting products are carefully inspected. Anything other than perfect is repaired/ replaced.