Biometrics for second visitors visa

My husband has to apply for his second visitor's visa and a friend tells me that, having done his biometrics for the first one, he will not need to do them again for the new one. Does anyone know if this is true please?

Not true ...

Simplistic logic: how do they know if he is the same person from the first application if they don't compare the biometrics? To compare they must ask him to submit them ...

True, except he would be submitting previous passport with visa. I must ask my friend why she feels it is not necessary. It is important as it affects the time we submit the application. Biometrics are done here once a month.

Ok ... Let's say I steal your passport with the visa and undetectably replace the photo ... how do they know?

Biometrics are given every time.