[morzh]

If I could avoid electrolytics altogether I would, but of course to the date theirs is the highest capacitive density, hence for some capacitance/voltage combinations there is no simply any other choice.
Also electrolytics are the cheapest way to get a high capacitance.
Say, when designing low voltage DCDCs when I need a low ESR cap I use X5R ceramics as they can reach over 100uF at 6 to 10V working voltage. However they are also expensive.

However electrolytics have the shortest lifespan of all, overly sensitive to temperature and used at their max current rating (ripple vs temp) will live as little as 2000 hrs.

Luckily in tube radios they are usually not used at their max rating. Still when buying, I try to get the max ripple rating at an acceptable price. This will ensure a long life.
This is why it is usually a good idea to know what the ripple rating is that the capacitor is subjected to.