This is the old value added story — somewhat low stability, a lot of error (though this error likely decreases with more years of data). (voices.washingtonpost.com)
They can not survive even for one day without proper encapsulation and this results in low stability. (sciencedaily.com)
An early study by Gary Becker and colleagues (1977) found that the relationship is non-linear: at first, increases in age at marriage are associated with greater marital stability, but after a point, additional increases are associated with lower stability. (contemporaryfamilies.org)