I've slept up to 12 hours in the Breezehome bed and don't get the well rested perk when I wake up, like I did in my room in the College of Winterhold.

It works fine for me.....

Are you sick?

Go to a temple and get a blessing or drop some potion.

have you maybe done some of the companions quests?

I think it doesn't show the "well rested" message when you wake up but the effect shows in the active effects tab.

This.

I've always got it when I slept there.

3 reasons that I can think of :
- werewolves do not get rested bonuses, ever
- users of the "lover stone" are considered under permanent "rested bonus" so they cannot get anymore through rest
- it's possible the game forgot to display the message on top of the screen but the effect is still active

ditto

Ahh, I activated the Lovers' Stone and have noticed that I haven't had the "well rested" displayed in ages. This explains it.

It's all the racket coming from the smith next door...

Ah! And, that's probably why stuff keeps falling off shelves and tables. Bloody Pirates!

A slightly related question. . . does Heavy Armor prevent getting "Well Rested"? I started a new character last night, a Red Guard 2-handed warrior/smith. After leaving helgen with the legionnaire, and arriving at Riverwood, and equipping some heavy armor, I then slept in the Smith's bed. I slept for like 10 hours. When I woke, I had the "Rested" 5% perk, not the "Well Rested" 10% perk. I suppose I may have gotten a disease and just haven't noticed - I'll have to check tonight, but I didn't really think it was possible to get a disease from anything in the Helgen escape dungeon, and we only encountered like 2 or 3 wolves on the way to Riverwood. I don't think I got a disease.

So, does heavy armor make it so you only get "rested" instead of "well rested"?

Well rested is for sleeping in a bed you own. You don't own other people's beds.

Those both cover me. The load screens mention the werewolf blood thing, but I didn't know that about the Stone.

When you rent a bed at an inn, is it considered 'owned' by you for that day?

Ok, thanks for the explanation, anyhow. I don't really know how that makes any sense, really, though. If a friendly NPC let's me sleep in their bed, why would I be any less well rested than sleeping in my own bed?

That's what I found out in my case. I slept 10 hrs. in my bed in the College of Winterhold, got the "well rested" message and "All skills improve 5% for 8 hours" showed up in my active effects. I then waited 10 hours and slept in my Breezehome bed for 5 hrs. Upon awakening I got no message, but "All skills improve 10% for 8 hours" was in my active effects.