Hi @herorareheart ,
Try the well known suppliers i.e. mouser.com, digikey.com, farnell.com just to name a few.
They all stock from different manufacturers so there’s a variety to choose from.
Capacitor quality has improved since a bad patch in the old days but one reason that they may fail prematurely nowadays is that sometimes the ones chosen are working for too long near to the top limit of their VW (working voltage) rating which places more stress on them e.g. using a cap with a 10VW rating in a circuit working at 9V instead of choosing a cap with a rating of 16VW to give a bit of a margin. This is to save money of course as the price goes up with the rating. This does add up over 1000s of components so it’s an understandable practice by the device manufacturer. This is what I think anyway.