The term of your automatically generated Future Renewals can be standardized in the Setup page. Under the "Mappings" subtab and the "Transaction Mappings" section, find the "Renewal Term" drop down.
The options here are:
- 12 months : Sets the future term to 12 months
- Match Previous : Uses the prior Opportunity's Term value.
In addition, you can set the renewal term as "1" using the renew as month to month setting: https://tyso.freshdesk.com/support/solutions/articles/16000083028-renew-as-month-to-month