Depending on your plan, the number of monthly uses for each tool varies. Some of the tools have usage trackers, like Follow-Up, to let you know when you're at risk of running low.
All of the tools have usage limits set significantly above most individual company's needs. Helium 10 publishes the limits on the tools that might impact a business' choice of packages.
Limits are implemented so we can ensure and manage reliable client access to the software, and to prevent excessive strain on the software by one user, which might negatively affect other users' experiences. It is extremely rare for an individual seller or company to exceed their usage limits, especially at the Diamond and Elite plan levels.
If you find that the plan you are on proves insufficient, you can contact customer service about changing to a plan that meets your needs.
See the chart below to find out the number of uses you have available according to your specific plan.