idioms - The quality of things you stick with

I was wondering if there is a word in English to describe the quality of things we stick with.

For example, if a training is well designed, people will tend to keep using it. Meanwhile, if it's not, they will tend to use it less and less until they give up on it completely.

There is the informal word "stick-to-itiveness" (also spelled "sticktoitiveness"), of course, but it is used as a noun, as a synonym for determination, a quality that a person has -- meanwhile I'm interested in the quality that an object or product would have.