I just bought all the DLC that was one sale even though I have yet to finish any questline on any of my characters.

I know that sometimes DLC can change a game's overall experience, not just the experience while completing the DLC. I would like to know if there is any reason to hold off on installing the content until I am ready to play it?

If possible please avoid story/lore spoilers and just let me know if there is something that will majorly affect my current saves/characters. TY!

P.S. I remember hearing something about NPC's being killed after installing one of the DLCs if you let it sit for too long. These are the kinds of things I'm most concerned with.

Dawnguard random vampire attacks in cities, might wanna hold off until you do all the vanilla quest you wanna complete, otherwise the quest giver might become a victim.

i find that to be not the case 75 % of the time on master difficutly. everyone is buffer than you lol.

Quest givers are essential until the quest is over. Even then, they may still remain essential. The Vamp attacks are complained about because merchants may fall victim and cut the player out of a place to shop. That is a sad excuse, in my eyes, as there are merchants all over Skyrim.

It really doesn't matter when you install the DLC.

It's no different than having all the DLC and starting a new character.