What is a best practice to calculate Opportunity Amount from One-Time Charge vs Contract Amount?

So I'm running reports in the Salesforce Org and trying to calculate Opportunity revenue from Amounts from Opportunities won and lost. However, there are one-time charges (say sign up fees to cover initial setup) and reoccurring charges that repeat monthly (amounts due every month for life of a contract). Contracts expire and are renewed at random times throughout the year.

So I'm creating separate custom fields and formulas to calculate revenue for this month, quarter, etc, but also the life of the contract. And say there is an annual contract that ends this month, customer hasn't renewed (yet), the deal isn't lost, but it's hard to get visibility that a good source of revenue might be lost. Is there an industry best practice on how to handle/show this? What have you done in your org to show this in reports?

There are other factors that come into play, items are commissionable (part of a Sales Rep's commission), but only some items and up to a certain percentage. There are other considerations, but first things first. I wanted to get an idea of what people are doing and best practices first. 

Thanks in advance.