diff --git a/app/models/user.py b/app/models/user.py
index a261697..c03b728 100644
--- a/app/models/user.py
+++ b/app/models/user.py
@@ -40,7 +40,9 @@ class User(BaseModel):
     ]
     expire_strategy: UserExpireStrategy
     expire_date: datetime | None = Field(None)
-    usage_duration: int | None = Field(None)
+    usage_duration: Annotated[
+        int, Field(le=9999 * 365 * 24 * 60 * 60, description="usage_duration must be less than 9999 years")
+    ] | None = None, 
     activation_deadline: datetime | None = Field(None)
     key: str = Field(default_factory=lambda: secrets.token_hex(16))
     data_limit: int | None = Field(
diff --git a/dashboard/src/modules/users/domain/schema.ts b/dashboard/src/modules/users/domain/schema.ts
index 7830b62..f74e8f2 100644
--- a/dashboard/src/modules/users/domain/schema.ts
+++ b/dashboard/src/modules/users/domain/schema.ts
@@ -17,7 +17,8 @@ export const UserSchema = z.object({
         .nullable()
         .optional(),
     expire_strategy: z.enum(["never", "fixed_date", "start_on_first_use"]),
-    usage_duration: z.number().nullable().optional(),
+    usage_duration: z.number().max(9999 * 365 * 24 * 60 * 60, { message: "usage_duration must be less than 3649635" })
+        .nullable().optional(),
     activation_deadline: z.string().or(z.date()).nullable().optional(),
     expire_date: z.string().or(z.date()).nullable().optional(),
     service_ids: z