There’s a tip in the game that says you should have your sims save up their simoleons because adventures can be expensive. I’ve found just the opposite – adventures are very profitable.
After your sims have gone through the various tombs in the three World Adventures destinations, always have your sims go back to walk through them again. The treasure and relic spawners within the tombs respawn throughout each tomb when your sims return to their home worlds. Since your sim already opened all the doors and disarmed the traps, she can just walk through the tomb collecting everything in a fraction of the time it took to explore the tomb in the first place.
This screenshot shows portions of five rooms in two different tombs under the Celtic ruins in Champs Les Sims. There’s a relic on the table nearest the camera, just out of the frame to the right in the corner of the next room is a money bag (the spawner is under a rubble pile the first time through this tomb), there’s a pile of ancient coins on the table in the middle of the screen, just behind that table (the small room that has a secret door entrance) is a gem spawner that sometimes produces extremely rare gems, and in the far background corner we can see another money bag. Treasure chests will also be refilled, so open them all again too.
The only places treasures don’t respawn are inside sarcophagi.