timppu: Take me for example. Ever since I was a kid, dentists always keep telling me how my teeth are so healthy and in good condition... but even I can see they are somewhat yellow, overall.
Caesar.: Same here. Actually my dentist once made me promise I wouldn't commit an atrocity and ruin my teeth with a "miracle" whitener product. She really likes my natural color, I guess, and wasn't fond of that kind of treatment.
Your teeth are going to be with you for the rest of your life (if nothing goes wrong). Perhaps you could seek the advice of a professional and then make an informed decision.
While a professional may be well informed... are they well intentioned? Here in the US, all medical care, including dental, mental, vision, etc., are pay per service. And here in the US, most Doc's offices are part of bigger corporate companies (whose priority is making money.. not health care). This does result in unneeded care being prescribed and done all the time. I don't know if it's that way in the UK but it appears to be heading that way in the whole world (the EXACT wrong way).
In other words, just because you seek a professional advice's, doesn't mean it's actually the best option for you. It may be the best option for the professional to make money.