Just a follow-up - I don't have any that run as long as 10 months, but I do have a few that run throughout the month, and could go as long as 6-7 weeks if staff really drop the ball on completing their tasks.  Those have been running that way for 6 years and since version 10.2 with lots of reboots and server restarts and I've never had an issue with the workflows just starting right up where they left off.

If you want an alternative, I would recommend having a database table to track these.  Whatever values are needed for the follow-up are added to the table, plus a status field and a follow-up date field.  The workflow from your form adds the record to the table with a status of Pending and the date that the follow-up needs to happen.  Another workflow runs on a schedule (probably daily) that checks the database table for any Pending records with follow-up dates on or before the current date.  If any are found, the follow-up is processed and the status on the database table is updated to Complete instead of Pending.  This option has the benefit of not relying on a workflow running for months.  But it does require two workflows (one to add to the database and one to follow-up) and the custom database table.  I do have a lot more processes that operate in this manner rather than delay activities for extended periods of time. 

But either option should work without issue.