Zoho CRM is only set up to handle once off deals out of the box. What should you do if you want to be able to forecast subscription revenue months/years into the future? If your customers renew every month, wouldn't it be nice to know how much you're likely to make in quarter three so you can see whether your pipeline is short or not?
Here's a Deluge custom function that you can hook up with a workflow to automatically generate potentials for future months. It won't duplicate existing potentials so you can set it up to run once per month and make sure you always have the next 2 years worth of revenue forecast.
Ideally you'd also have a function to change the status of future potentials when the master potential is modified. (E.g. if a customer cancels their subscription, the future potentials should also be nullified). Let me know if you'd like that function and I can build it for you:)