Aging in Tomodachi Life: Living the Dream is one of those systems that looks simple on the surface but has real consequences for how your island develops over time. Whether a Mii is treated as a child or an adult changes what relationships they can pursue, who they can marry, and whether they can eventually start a family. Get this wrong and your island's social life can stall in ways that are annoying to untangle.
How does aging work in Tomodachi Life: Living the Dream?
According to Game8's aging guide, every Mii on your island is classified as either a child or an adult based on their age setting. This classification is not just cosmetic. It directly determines the kinds of relationships a Mii can have, including romance, marriage, and family progression. A Mii set below age 18 is treated as a child, while those at 18 or above are treated as adults.
The game does not age Miis automatically by default in a way you cannot control. You have direct tools to manage this, which means the age of every Mii on your island is ultimately your decision.
A Mii's child or adult status affects romance and marriage eligibility. Set ages deliberately when creating Miis based on characters with established ages.
Mii age setting screen
How to stop a Mii from aging
If you want a Mii to stay at their current age permanently, use the Don't Age option when setting up or editing that Mii. This locks them in place so they never grow older over time.
This option is especially useful when you are recreating characters who have a fixed canonical age. A child character you want to keep young, or an adult character whose age should never change, both benefit from the Don't Age setting. Without it, their age can shift and potentially change how the game categorizes them.
Use Don't Age for any Mii based on a fictional character with a specific age you want to preserve long-term.
How to make a Mii an adult: the Age-o-Matic
The Age-o-Matic is a level-up gift that converts a child Mii into an adult. According to Game8, this item is one of the possible gifts you receive when leveling up a child Mii, so you need to have a child Mii on your island and get lucky with the level-up reward pool to obtain it.
Using the Age-o-Matic on a child Mii changes how the game treats them socially. Once they become an adult, they become eligible for romance and marriage progression that was previously unavailable to them.
How to make a Mii a child: the Kid-o-Matic
The Kid-o-Matic does the reverse. It turns an adult Mii into a child. This item is a possible level-up gift when you have an adult Mii, according to Game8's guide.
Converting an adult to a child comes with trade-offs. Child Miis have restricted relationship options compared to adults, so using the Kid-o-Matic on a Mii who is already in a relationship or married can have significant downstream effects on their social situation.
Changing a Mii to a child with the Kid-o-Matic can limit their existing relationships and restrict what they can do on the island. Think carefully before applying it to Miis who are already deeply embedded in your island's social network.
What does aging actually affect?
The effects of a Mii's age status touch several parts of the game. Here is a breakdown based on information from Game8:
The biggest impact is on long-term relationship planning. Married couples can have babies, but only adult Miis can reach that point. If you want a specific pair of Miis to eventually start a family, both need to be adults. Planning this from the moment you add Miis to your island saves a lot of backtracking later.
How to get the Age-o-Matic and Kid-o-Matic
Neither item can be purchased directly. Both are tied to the level-up gift system, and which one you can receive depends on the current age status of your Mii:
- Age-o-Matic: Level up a child Mii and hope it appears as the gift reward
- Kid-o-Matic: Level up an adult Mii and hope it appears as the gift reward
Because these are random drops from the level-up gift pool, you may need to level up multiple Miis before the item you want appears. Prioritizing happiness boosts and fulfilling wishes speeds up leveling, which in turn gives you more chances at these items.
The level-up gift system is random, so there is no guaranteed way to get the Age-o-Matic or Kid-o-Matic on demand. Keep leveling your Miis and the items will eventually appear.
Planning your island around aging
The most practical approach is to decide a Mii's long-term role on your island before you add them. Miis you want in relationships and families should be adults from the start, or at least have a clear plan to use the Age-o-Matic on them. Miis based on younger characters who should stay children can have Don't Age applied immediately.
Changing a Mii's age status mid-playthrough is possible but disruptive, especially if they are already involved in active relationships. The Kid-o-Matic in particular can create complications that take time to resolve. Treat age settings as a foundational decision rather than something to adjust casually.
For more tips on managing your Miis and island life, browse more guides covering everything from relationship mechanics to island expansion strategies.