Github announced yesterday that all of their paid plans now will include unlimited private repositories. So if you are individual developer, no matter what you were paying before, your plan will now include unlimited repositories. This is not the case for organisations where you will get the option to upgrade to unlimited private repositories at any time. This may affect the cost structure of companies if they decide to go for the upgrade so its better to evaluate first how to best manage the members and repository access.
If you are paying based on repositories you use, you can upgrade or downgrade in the legacy repository structure based on the repositories you need. Also Github is not enforcing any timeline to move and if in the future if they decide to set a timeline you will be getting at least 12 months as per their statement.
This is a great move by Github but services like Bitbucket and Gitlab has unlimited repository option for a long time. Both Gitlab and Bitbucket offers unlimited repos for free, while the former allows unlimited collaborators and the later with team up to 5 members. Way to go Github.