Rejuvenate a SIM in The Sims 2, you can use the elixir of youth. It can be purchased in the rewards for the points that are given for the fulfilled desires of your character. Elixir is a green liquid in a large glass vessel. One serving of the elixir rejuvenates SIM for 3 days.
If you play The Sims 3, decide how you want to rejuvenate your SIM. There are only two ways. The first way - rejuvenation for one day: SIM needs to eat the fruit of life - a particular plant, whose seeds can be found in the city. 1 eaten the fruit rejuvenates your SIM for 1 day, 2 fruit, 2 day, etc.
The seeds of the fruit of life can be found at research Institute or at the cemetery. These seeds are from "unknown special seeds". Planting such a seed you can grow and other special plants like fiery fruit or the flower of death, so it will be better if you plant some special seeds. And don't forget one important detail - a special seed you can plant to level 7 gardening.
So, if you managed to catch the fish-death to grow the fruit of life, you can cook Ambrosia - food of the gods. She will return your SIM to the beginning of the age period. While your SIM is in a good mood for 7 days.
Also, you can resurrect a dead character with the help of ambrosia. After one family member dies, you receive a call from a research Institute with a proposal to resurrect it. You bring the ashes of the deceased in a scientific Institute and the Ghost of the deceased joins your family. Then, forcing him to eat the ambrosia, you will see how he again becomes a living character.
If you can't get the right ingredients, you can extend the life of their characters by changing the parameters of the game. For this you need to select the menu "Settings" and open the tab "game Settings". There find the "Epic life" and prolong it as much as you want. Thus, the number of days of one age period is not standard, but the way you choose. It should be remembered that this setting applies to all characters in the game.