When do you decide a unit must be switched out? I am an employee of a medical devices company and we have a diathermy device that in all honesty as long as it is taken care of will go on for at least 10 years. We have been asked by some hospitals what the lifespan of the product is, when should they replace it?

Obviously our company would like it if a new unit was purchased on a more regular basis and shorter time period as we would make more money. e.g. new unit every 5 years rather than a view of if it is properly maintained and is functioning safely then it doesn't need to be switched for potentially twice that amount of time, especially if it still works and does so safely.

Has anyone come across a situation where they are being encouraged to switch out units due to their age alone despite still being fit for purpose? Is so, how did they handle it and what were the biggest obstacles they faced? I'm loathed to put my name to anything which says a unit must be changed after a certain time for any reason if I am sure that with proper care and maintenance it will be fine for a longer period of time.