True, whilst many components will continue working 'as is' those that are potentially suspect in the future are worth swapping out now while you have the chance. Unless you relish the thought of doing the same exercise again in the not too distant future. Each to their own. Anything that is potentially dubious I would replace. Preserving originality, a worthwhile objective, but if it means you have to go through the same or a similar exercise in five years time...I'd rather deal with it now, not then.
There is also the reliability aspect, it worked last week, why not today? Oh! R325 has gone high...I should have replaced it while I had the chance...for the cost and potential disappointment factor just deal with it now. Don't procrastinate...(I'm saying that with a smile on my face, one could say, 'Fatherly advice.'...I should listen to myself sometimes!).
Steve A.