I was tired of having a follower entourage everywhere I went inside my own home. Opening dialogue and dismissing them - how annoying.
So I just released this mod. Thought I'd invite the community to check it out.
Other follower mods might exist that do this, but I couldn't find any. It's a simple mod that should be compatible with everything under the sun.

Link: http://www.nexusmods.com/skyrim/mods/68043?

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* Followers at Home by Puff The Magic Dragon *
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Description
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Your loyal followers are now just a little more laid back - enough that they stop following your every footstep when you're at home.
They will sandbox and sleep instead of haunting you while you're at home, but come right back to your side when you leave.

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More Details
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You just got back from a long three weeks of adventuring. You're tired and sore and dirty. You walk in the front door and head off to take a shower - and your three loyal followers are so loyal they follow you right in!
Wait!
Aren't they at home? Can't they go do their own things?
Yes. Now they can.

I made this mod because I was tired of Serana following me all over our house like a lost puppy. This mod automatically applies packages telling her, or any follower, to sandbox around the house as soon as you walk in the front door. Leave the house, and she's right back at your side! No more telling them to relax when you get home and then recruiting them again when you leave! I was unable to find any other follower mods that provided exactly this functionality. (Perhaps some of the major follower overhauls do this, but none of them mentioned it in their descriptions.)

There are a couple of variables that this mod uses to make this work: The global variable playerFollowerCount needs to be higher than 0; the follower needs to be in the CurrentFollower faction, and the follower's ActorValue "WaitingForPlayer" needs to be 0. For those who aren't modders, this means that this mod should work with any and all followers in the game, as long as they are actively following the player. This mod currently supports up to 5 active followers - if you have more than 5 active followers at a time, something is very wrong with you (and your extra followers after the first 5 will behave as normal). This mod triggers whenever you enter a location with the keyword "LocTypePlayerHome", which should cover all vanilla and DLC player homes and most player home mods.

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Requirements
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Skyrim v1.9.32

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Installation
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Recommended NMM:
Click and run!

Manual:
Extract the files directly into your \Data folder.
Activate the mod in your Skyrim Launcher

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Removal
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Reverse of installation.

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Compatibility
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This mod should be compatible with every other mod out there. Theoretically.
It should even work with the many follower mods and follower overhauls. If you find one that is incompatible, let me know.

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Known Issues
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I actually haven't found any. Please let me know if you find something.

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Version History
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Version 1.0 - Finally, some privacy!

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To-Do List*
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This might just be the simplest mod in the world.

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Credits goes to:
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Many thanks to Bethesda for making such an awesome game and for making the construction set that lets people like me with way too much free time modify the game.
Thanks to God for creating us all!

I really need to see how you did that.

It was super easy. Probably the simplest mod in the world.

Two quests - puffFollowerAtHome and puffFollowerLeaveHome.
pufFollowerAtHome has 5 reference aliases that fill based on conditions: subject GetIsInFaction CurrentFollwerFaction AND subject GetAV WaitingForPlayer is 0.

puffFollowerAtHome has 1 location alias that is filled based on the event data: NewLocation
Two packages - a sandbox package and a sleep package, added to the quest aliases, and pointed at the Location Alias on puffFollowerAtHome.

A Story Manager stacked quest node with conditions: NewLocation HasKeyword "locTypePlayerHouse" OR OldLocation HasKeyword "locTypePlayerHouse"
puffFollowerAtHome starts if NewLocation has the keyword, puffFollowerLeaveHome starts if OldLocation has the keyword. (puffFollowerAtHome is first in the stack.)

So you change locations into a player home, which fires off the Story Manager event, which starts the AtHome quest, filling the aliases with available followers and giving them the packages to sandbox or sleep. The quest has a higher priority than the vanilla follower quest, so these packages override the vanilla follower packages and off your followers go to do whatever.
You then change locations leaving a player home, which fires off the Story Manager event, which starts the LeaveHome quest whose sole purpose is to stop the AtHome quest (and itself). Your followers now revert to whatever behavior is normal for them - generally that means following you out the door and into the world.

If the interior location has the keyword and the exterior location has the keyword (typical for most player houses), leaving the interior location will not stop the AtHome quest, so your followers will continue to sandbox (though the quest will get reset and they'll still follow you outside, because it's first in the stack). Leaving the exterior location into the wilderness or anywhere else without the keyword will stop the AtHome quest and your followers will catch up to you.

And now I've given away all my secrets.