TIM Enterprise imposes no limits on the number of users you can log. The smallest version available allows you to log 100 users but larger versions allow you to log several hundred thousand users.
Cross-product upgrades attract a full refund of the lower value product meaning there is no penalty for growing!
Using TIM Enterprise with MySQL or MS SQL databases the amount of data that can be stored varies depending on the version of database being used. Typically this will be multiple GB of data up to a few TB.
When using a native database the system can store up to 4GB of records. A typical record is about 4KB in size.
If space gets tight, old data can be archived to another location, to be imported and inspected at any time in the future.