Even Tantalum capacitors have a service life just like Aluminum electrolytic. While the aluminum ones might leak with age they generally fail open (no big deal) while tantalums fail closed (short and sometimes a big bang bad for the circuit).

When I recap my boards I use the same type as was on there, if they last another 15 years then I will recap them again if needed (probably not since they wont get the same use). All the ratings are based on temperature when running and hours running.