Played vs Unplayed

Here are the differences between played and unplayed households

• Their aging settings can be set differently.
  
• Unplayed sims change their jobs to either be co-workers or fill in a service sim spot (maid, vendor etc). Played sims will never change their jobs on their own.
  
• In university, unplayed sims will re-enroll on their own while played sims will wait for the player to re-enroll them.
  
• Building in houses owned by unplayed sims will not spend their money. Instead you'll be in free build mode (infinite money, no household inventory) like when you are building in an unowned lot.
  
• To make sure there are sims in the Realm of Magic, unplayed sims may be turned into spellcasters.
  
• Only unplayed sims' houses and community lots can be crime scenes.
  
• Unplayed sims' phone skin may get set to default.
  
• Unplayed toddlers', children's, and teens' character values may go back to neutral (spot where they started off).
  
• While unplayed sims won't lose skills, they may suddenly become a master in one when they become a service sim.
  
• Unplayed sims will get more relationships culled.
  
• If the game is forced to generate a new club (happens when you have less than 10 clubs in game), it will be filled with unplayed sims.
  
• Many have mentioned culling. All sims who are in My Households section won't get culled. While all the played sims are in that section (putting them to other households will also make them unplayed), unplayed sims that you want to protect must be put there.

The main benefit of unplayed households is that you can edit their house for free. The main drawback is that they change a lot without players help.