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.
Most tools have usage limits set well above the majority of any single company's needs. The limits are implemented primarily to prevent excessive strain on the software servers by one user, which might negatively affect other users' experiences. Individual sellers and companies rarely go over their usage limits, especially at the Diamond and Elite plan levels.
If you find that the plan you are on is 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.