Most new 'lytics I have bought and checked arrived with the expected capacitance & leakage values. I don't think they need to be formed, as that is done in the mfg process when the caps are polarized & formed. ESR is a consequence of the structural aspects of the cap and doesn't change noticeably with use, if the cap is not severely abused with excessive ripple current or applied voltage. Basically, you get what you order straight up from the reputable mfrs. The story could be different, however, for very old 'lytics that have sat around in little ol' radios that have not been played in an eon. They need to be gently nursed back to health if they are not in the same shape as the dried out insect shells found in the radios.
