It's been about 45 years since the first Tantalum capacitors were introduced in Neumann transistor ("FET80") mics.
They rarely gave me trouble in the past. Aside from the occasional blow-out after a massive voltage shock from phantom-power oversupply (they don't like to digest much higher voltage than what is printed on them), they've been pretty stable. Their lousy sound is another issue for another topic.
But lately I have found that if I do any service work where other components are replaced, or if I just look at those red buggers the wrong way, these Tantalum drops are starting to give out more and more, steepening that long, almost straight line of the reliability curve over time of the past forty-five years noticeably downwards.
So, if you find your Neumann Fet mic from the early 1970s suddenly without output, look there first.