There are many different answers to this question. Some think that the sign is still useful if the message on the sign can somehow still be read, even if the print has already faded and all that remains are a few shadows of the original legend. We cannot disagree more strongly. Warning signs and pole markers are meant to be read easily. Signs and markers are about fast and impactful communication, not about deciphering an obscure message. You shouldn’t have to be a CIA agent or an archaeologist expert at gravestone rubbing to decode a sign! Useful life means not only that the sign or tag is readable, but that its original impact has not significantly deteriorated.
 
  

	Sign in Connecticut laminated with Lexan yellowing and delaminating after 5 years. An adhesive is the "Achilles Heel" of any rigid sign. It is inexorable human nature to peel the corner back on a rigid sign. Although the right laminate does, indeed, provide some protection, too often overlaminates are chosen poorly. What might look glossy and abrasion-proof in the first year often fades or yellows in subsequent years.
	Baked aluminum sign in NY chaulks after 7 years. New inks and superior baking results in signs that are much more durable
	Red inks are the most transitory of all. Circle around "Mr. Ouch" has faded.