By imposing locks on your software, you can freely distribute your product for trial or evaluation, and rely upon lock expiration to compel purchase of your wares when the evaluation period expires. When software locks expire, your prospective client must purchase a valid license.
You can also set Expiration Days, Expiration Date, Global Time and Executions limits an IntelliLock locked assembly. When license locks expire, your customer must acquire a further license to further use your product.
By combining trial locks with license locks (license files which are restricted itself) you can impose any limitations on software use you desire. Most importantly, without writing a line of code to do so, you can show off your wares to your market.