Does it matter how much you sleep? Should you worry that you sleep too much or too little?
Only if it impacts your daytime waking life.
There is usually no particular biological or health reason to worry about sleeping less or more than other people. Your spouse might get mad at you if you sleep too much and you might get into hot water if you nap on the job, but most people have no reason to worry about going outside the norms when it comes to sleep duration. You might think sleeping too much is a problem, that excessive sleep is a waste of time, and indeed hypersomnia is recognized as a clinical condition. But not all long sleepers can be classified as hypersomniac and in any cases, there is nothing doctors can do for hypersomnia except prescribe stimulants. So it may not be worth worrying about.
"O sleep, O gentle sleep, nature's soft nurse, how have I frightened thee, that thou no more wilt weigh my eye-lids down and steep my senses in forgetfulness?" - Shakespeare
Sleeping past normal wake-up time can lead to post-sleep inertia aka worn-out syndrome. This is arguably a form of jet lag: the body is "out of time" and the person feels lethargic and muddy-minded.
What happens when we miss sleep? And then make it up. Even with free recovery, only 1/3 to ½ of lost sleep is recovered. All the lost deep sleep is recovered and about ½ of the REM sleep. Time spent in light sleep is lost.
The worse the insomnia, the worse the scores on subjective quality-of-life surveys. Is the reduced quality of life due to the insomnia or to the excessive daytime sleepiness or to the other background effects of sleep deprivation? It seems impossible to disentangle these.