A section requiring that the contractor guarantees his work against defects in workmanship and materials for a period of two years from the date of completion is sometimes incorporated in a specification. Such a condition, however, is better left out. With the exception of a very few grades of fixtures no materials entering into the makeup of a plumbing installation are guaranteed. Care is exercised to send out only goods which are sound, flawless and in good merchantable condition, but if after the lapse of several months, or weeks, for that matter, the goods fail for any reason, it is at the owner's expense. As the materials which the architect specifies are not guaranteed, the insertion of a clause in a specification requiring the plumber to guarantee other people's wares imposes upon him the duty of an insurer of goods, and if the contractor be a responsible one he will allow in his estimate a sufficient amount to cover any possible damage, however remote, which might occur during the two years he is responsible for the plumbing. Irresponsible contractors might ignore the clause, having no intention of living up to it, but in that case the responsible contractor is put at a disadvantage and might lose the work to an indifferent and irresponsible one on account of the guarantee. At its best such a clause is an additional expense to the owner. With the merchantable goods now on the market the repairs due to defective materials in the two years succeeding completion of a contract will be so slight that they will cost the owner much less than a responsible contractor will exact for guaranteeing the work for that length of time. He has to figure on possibilities to protect himself, while the owner would have to pay only for actual repairs.