WordSmith licences are perpetual and you may re-download as often as you need. However a version 5 licence will only work with version 5, a version 6 only with version 6, etc.
This is a licence for an organisation. Requires installation on a shared folder. Limits the number of concurrent users at any given time.
This is a licence for a person. For an organisation allows any one user to use on that one computer. For individuals, allows use at work and at home under certain conditions.