If you're planning to deploy applications on PWS, it's important to understand the limits of the platform. This article discusses the limits in terms of the number of applications or application instances that you can deploy.
Each organization on PWS has a quota and the system will cap your organization to prevent you from exceeding this limit. There is no hard limit on the number of applications or application instances that you can run, but you cannot exceed the memory quota for your organization. This means you can continue to deploy applications or application instances, so long as you remain below the memory quota.
The default quota for a free trial org is 2GB while the default quota for a paid user is 10GB. To confirm the quota for your organization, look in the Developer Console at the top of the screen once you've selected your organization. It is listed directly in the middle. Alternatively, it's also visible from the command line by running `cf org <your-org-name>`.