As you have now realised, if you don't have a datasheet for the cap you are measuring then it is guesswork as to how to interpret a measurement. As you will have read, ESR levels vary very widely between brands/models, temperature, measurement frequency, meter (if not using an actual ESR measurement technique), and other factors. If you don't have all those ducks in a row and accounted for then don't try to guess based on ESR. Just plucking a value out of the air, or because someone uses a particular line-in-the-sand value is imho just perpetuating a guess.
If you got sold an ESR meter based on advertising spiel, then watch out for other snake oil advertising.
If you are fortunate enough to have made notes on brands and cap values and their ESR values, and come across the same model/value caps in other equipment, then you may be able to assess outlier parts, similar to measurements on a part that you have a datasheet for.
ESR, no matter what frequency it is measured at (within reason), can degrade with age/abuse. So can cap leakage and cap value. If any one of those parameters changes outside accepted tolerances then you have an indicator, and can make a judgement call on whether or not to replace the cap, and for what reason.