How fast can my downgraded account be restored to a monthly paid account?

If I downgrade to a free or Starter account from a monthly paid account, how fast can I upgrade back to a pay account, like Bronze for example?

This question is posed given the following context:

I'm interested in the Bronze account for four or five months during a calendar year, and reverting to the free or Starter account for the remaining months of the year. When the time comes to upgrade back to the Bronze account, how quickly can this be done? A few minutes? Hours? 

Thanks

Upgrading the subscription plan will immediately take effect on your account.

User guide: How-to-Upgrade-My-Account

The least subscription payment schedule plan is Monthly (there is Yearly and Bi-Yearly). The subscription renewal is automatic. So if you subscribe with the monthly plan, it will auto renew on a monthly basis. It will only stop if you cancel the subscription.

When you cancel the subscription it will be applied immediately as well. The subscription will not renew anymore after it reaches the subscription expiration date. Take note that since subscription is monthly, you will still retain the plan up to the date of the payment schedule of the subscription (expiration date).

Example, if you upgraded to paid plan on the 23rd of the month, it will be upgraded immediately. Then, you cancelled/downgraded the subscription on 25th.. the subscription will remain at the paid plan (i.e. Bronze) up to until the 23rd of the next month. 

User guide: How-to-Downgrade-Subscription-Back-to-Free-Account

Hope this help. Let us know if you need further assistance.