ともなると

ともなると is used to indicate that when something reaches a particular stage, level, or situation, certain natural, expected, or unavoidable consequences occur.

It emphasizes that the change is not surprising, because it logically follows from having reached that state. The result often reflects common sense, social expectations, or reality.

This grammar is mainly used in formal or written Japanese, but it can also appear in serious spoken contexts.

Usage Notes

• ✔ Expresses a natural consequence

• ✔ Often used for age, position, situation, or scale

• ✔ The result is usually inevitable or expected

• ✔ Common in explanations and reasoning

• ❌ Not used for sudden or accidental results