By default, JMeter doesn't put timers in your test plans when a scenario is recorded. This is far from reality. Ideally, users will have a think or wait time between page views and requests. Getting JMeter to simulate such pauses or waits makes your test plans more realistic, bringing it closer to how actual users may behave. JMeter offers various built-in timer components that help achieve this. Each varies from the others in how it varies the simulated pauses. The following is a list of some of the included timers at the time of writing of this book.
The Constant Timer is used if you want each thread to pause for the same amount of time between requests.