My answer is 'why?'
If the headwind component is 10 knots or less.
If a specified maximum increment is stipulated by the QRH
In manual flight, people don't generally fly their selected speed anyway (it's more than likely faster) and in most cases the only answer to why they want to fly a 'few knots faster' is to achieve a smoother touchdown. All a load of twaddle that has crept into the operation over numerous years by people who think they know better.