Subscriptions renew monthly based on the date you originally subscribed. If a month doesn't have that date, your subscription will renew on the last day of the month (example: January 31st vs February 28). Renewal timing may vary slightly.
If you have a yearly plan, your plan hours refresh monthly on the same day. For instance, if you subscribed to a yearly plan on August 8, your plan hours will refresh on the 8th of each month.
To easily find your renewal date, you can either use the info command in Discord or visit your Manage Subscription Page on midjourney.com. Using Discord will show you the exact time your plan will renew.
Your renewal time may vary up to an hour from what's shown in Discord due to Daylight Saving Time/Summer Time.
Remember, all Midjourney subscription plans automatically renew unless you set your plan to cancel.