Question: what questions to ask when buying double glazing?
Answer: How much experience do you have? It's important to establish how much industry experience a company has. ... 
What do your customers think of you? ... 
Do you have any accreditations? ... 
How much will it cost? ... 
Do you offer guarantees? ... 
Do you use your own employees? ... 
Do you have a showroom I can visit? ... 
How long will it take?