I replace all premade households that have been placed in homes or apartments. The only exceptions are Vlad and Caleb. I also don't delete L. Faba, Morgyn, or Simeon so I don't glitch them. I use MCC to copy and paste edited models of them that I have in My Library. I do the same thing with Salim.
Windenburg pre-made households are the exception to blanket deletion because they're tied to clubs. It takes a bit longer to replace them but it's worth it to me so I can fix their fake skills, balance their traits, and make any other necessary changes. Like why is Morgan with the Good trait in the Renegades club? And why is she a Teen? In my game, she's not "good" and she's not a teen anymore. How many creative females do I need? How many "good" or "cheerful" or "romantic" Sims do I need? Music Lover and Loves Outdoors are two other traits that are over-used with premades.
It's also worth spending time replacing Windenburg premades because when they're all deleted at once the game creates replacement clubs whether you want them or not. If that's not bad enough the game also picks a leader for each club. In one game Father Winter was the head of a Diving Club and Vlad was the leader of a Video Gaming club even though he doesn't own any electronics.
Do I have any regrets about replacing premade households? Nope. I don't like how traits and skills were handed out so my replacements fix that. Plus, there are some premade households that I just don't like (Partihaus) or who I have found serve no purpose (Behr, Bro, Free Spirits) so they get the axe sooner rather than later.
ETA: I forgot about Erwin. In one game he became the leader of a Comedy Club. Geez.
