The only time you may have to think about a guarantee is when a customer has had a problem and is demanding something be done. At times like that, you may be stressed and not making your best decisions. This is why you should develop a guarantee policy in advance of this happening.
A guarantee policy also serves to protect the business against customers who cannot be satisfied or generally unhappy customers.
A guarantee can take many forms and this needs to be communicated. Will you offer a cash refund or a store credit note and what conditions apply such as requiring the original receipt? Will the product be replaced and is there a time limit after purchase where this no longer applies? The guarantee policy may involve repairing the product in house or being sent our for repair. Who covers the cost and will a replacement be provided while the repair is done are other considerations.
There is a lot to think about on the subject of guarantees which is exactly why you don’t want to be on the spot and trying to figure things out with an unhappy customer beside you.
If you have a no questions asked guarantee, this could be a way to stand out from you competitors. When completing the SWOT, Strengths Weaknesses Opportunities Threats table, if you discover none of your competitors provide a guarantee and this was identified as a weakness by customers, then offering a guarantee could be your opportunity.