I have a level 65 character, who has done most things in the game (++open world exploring, Harbinger, ArchMage, destroyed the DB, almost completed the TG, latter part of the MQ, halfway through DG).
But lately it has started to feel like a "need to get this job done" kind of situation.
I am not the type of person that can 'not finish' something, so I keep grinding it out.
I also feel the numerous CTD I experience for who knows what reasons (some certainly related to mods, but which ones? as TES5Edit and SaveGameCleaner, and LOOT - which just messes things up, and CK are not always fixing).
So, how do you keep it 'fresh'? I played DA Origins through many times (all origins to Ostagar, Mage/Noble through several times, unmodded, modded), and the characters kept me involved, as every play through you could notice subtle differences in the relationships with the NPC companions.
Skyrim just doesn't offer this, so what makes the game for you?