Disparities can result in challenges, they can also create positive outcomes.
Most people believe that compatibility is high on the list of relationship success. Yet, in over four decades of working with couples, I more often observed the opposite.
Though those disparities can result in significant challenges, they can also create positive outcomes. It depends on how important each need or desire is to each, and how they work to resolve the gaps that exist.
For instance, it is very common for a night-owl to partner with an early awakener. Or a super-neat person to end up with someone who is comfortable with clutter. One is attached to future planning while the other wants to live more freely in the present.
There is a common assumption that mismatched people find each other because opposites naturally attract. In my more than four generations of working with couples, I have come to believe that that are deeper reasons for that phenomenon to be so common. In the case of mismatched sleeping schedules, for example, it may be that disparity allowed for greater tribal survival if someone was always awake to watch for potential threats. Or, does too much compatibility predict boredom? Or, do people in some way become more complete by vicariously living through the other partner?