My DD1 struggled for years to unwind / relax at bedtime, and then didn't wake up well in the morning. She finally learned around age 11, but if she gets too long a lie in it can go to pot for 2 or 3 days again.
Because of this we still stick to minimal lie ins at the weekend and school holidays. On school days wake up is 7:30, at weekends/holidays it is 9am latest. It works well for us (especially as DD2 is alwys awake by 8 of her own accord)
On the other hand, they do say teens start needing more sleep and aren't good with mornings .......
ds2 is 11 and off to senior school in September. He has a tendency to be lazy in that he's hard to wake up and then very slow to get dressed, 45 minutes to get out of pyjamas wash under arms and face, get into uniform that is already laid out and downstairs for breakfast.
I'm pretty sure this stems from his lie ins at weekends, now the ootball, rugby and lacrosses season is over he doesn't have to be up and out of the house ready for matched before 9am so will stay in bed sleep. I never used to mind this as he'd still get up at 6, watch tv while eating breakfast and then get showered and dressed. But since he hit 11 he really struggles wih waking up.
Would I be unreasonable to start enforcing a no lie in rule, so everyone up and ready by 8.30 on a Saturday and sunday?