Thanks for getting in touch, and no offense taken at all.
Unfortunately, offering monthly or 3 monthly licensing would involve significant changes to our licensing servers and other infrastructure so we can't offer this in the short term. All our licenses are perpetual, meaning once activated we have no way to revoke them, they will never expire and you can continue using our products forever. In addition to the purchase of our plug-ins, we provide automatically a one-year / three-year maintenance plan. Once the maintenance plan expires, you'll be not able to upgrade to the latest releases (published after the maintenance plan end date), but you still can use versions released before that date.
There's no obligation to maintenance plans once expired immediately, nor any penalty for renewing them later down the line. if you'll not be using any new features and improvements there is no need to renew the plan, as your most recent valid version will remain working.
I hope that helps and in case of any further questions