This software is available to be used for free indefinitely. Full features are available for the first 30 days. Functional (not quantity) limits are placed after the 30 day trial period. None of your data is lost when the limits are placed but you cannot access some of the features. This gives you the opportunity to try the free version without losing your data. If you decide at a later date to activate the full feature version you will again have access to all of the data you entered during the evaluation.
Please see Compare Features for the differences.