They don't Tiny. The original condensers were made using the foil wrap method. A dielectric gel or film was applied to foil which was cut in strips and then to length and then spun on a machine into a cylinder and this was inserted into an aluminum canister. The ends made the contacts, and that became the capacitor. The ones made by Delco-Remy and Standard were very accurate. The ones made in China are horrible.

The problem 40 to 60 years later is the dielectric gel/film dries out and this causes them to stop working. If they're stored in a hot place, they can be ruined in less than 10 years...and that not surprisingly is why everyone was told to replace them anytime you changed points. The distributor being a hot place by nature.

~ Jon
1952 1/2 ton with 1959 235 | T5 with 3.07 rear end