Please let me know about "Boost Mode Validity Period".
Boost Mode will be valid for one month after purchase.
After initial purchase, the Boost Mode subscription will renew automatically each month*.
You can review your subscription’s validity period via the methods below.
1. Open Google Play Store
2. You can manage your subscriptions by tapping Menu = > Subscriptions
*Monthly period details:
・The subscription is valid until the same date in the following month from the last purchase or renewal.
Example) If the subscription was purchased or renewed on January 1st, it will be valid until February 1st.
・If there is no equivalent date in the following month, it will be valid until the closest date in that month.
Example) If the subscription was purchased or renewed on January 31st, it will be valid until February 28th.