DesignSpark Electrical is not time limited, or restricted in terms of the number of symbols or connection points. There is a limit of 15 pages per project, but the number of projects is unlimited. If you also require full PLC management capability, you can consider this upgrade.
If you feel that you will need more than 15 pages, please consider the Elecworks solution from Trace Software.
Various price options and store for buying the upgrades are available here: https://eshop.trace-software.com/en/19_electrical-design-and-automation